Base station apparatus of mobile communication system

ABSTRACT

A base station including a transmitting and receiving amplifier for amplifying CDMA signals exchanged with a mobile station; a radio stage connected to the transmitting and receiving amplifier for carrying out D/A conversion of a transmitted signal that undergoes baseband spreading, followed by quadrature modulation, and for carrying out quasi-coherent detection of a received signal, followed by A/D conversion; a baseband signal processor connected with the radio stage for carrying out baseband signal processing of the transmitted signal and the received signal; a transmission interface connected with the baseband signal processor for implementing interface with external channels; and a base station controller for carrying out control such as management of radio channels and establishment and release of the radio channels. The base station communicates with the external channels by mapping logical channels into physical channels. The CDMA signals are spread using a short code and a long code.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a divisional application of commonlyassigned, co-pending U.S. patent application Ser. No. 09/403,161, filedJan. 31, 2000 and also entitled “Base Station Apparatus of MobileCommunication System”, which application is incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. The Field of the Invention

[0003] The present invention relates to a base station in a mobilecommunications system, and more particularly to a base station capableof carrying out communications with mobile stations through high speeddigital communication channels using CDMA.

[0004] 2. The Relevant Technology

[0005] Recently, base stations in mobile communication systems havebecome increasingly faster owing to the development of novelcommunications methods such as CDMA (code division multiple access),which become possible with recent advances in digital communicationstechniques In addition, fixed stations are also digitized, and come touse new switching networks such as ATM networks.

[0006] Thus, new base stations are required which meet such advances intechnology.

BRIEF SUMMARY OF THE INVENTION

[0007] An object of the present invention is to provide a novel, highspeed, digital base station best suited to achieving communications withmobile stations by CDMA, and with a control office by ATM.

[0008] In the first aspect of the present invention, there is provided adigital radio communication system comprising: transmitting one or moreknown pilot symbols at every fixed interval; and receiving, on areceiving side, the pilot symbols, and carrying out coherent detectionusing the received pilot symbols, Wherein a number of the pilot symbolsthat are transmitted periodically is variable in accordance with atransmission rate. According to the configuration above, a trade-off canbe optimized between degradation in accuracy of coherent detection dueto a reduction of the number of the pilot symbols and an increase inoverhead due to the increase of the number of pilot symbols.

[0009] In the second aspect of the present invention, there is provideda digital radio communication system comprising: transmitting, on atransmitting side, one or more known pilot symbols at every fixed slotinterval; assembling a frame from a plurality of the slots; andreceiving, on a receiving side, the pilot symbols, and carrying outcoherent detection using the received pilot symbols, wherein the pilotsymbols consist of a known pilot symbol portion and a sync word portionfor frame alignment. Here, the pilot symbol portion and the sync wordportion may be transmitted alternately at fixed intervals in the pilotsymbols. The receiving side may carry out the coherent detection usingthe known pilot symbol portion, and may employ, after establishing theframe alignment using the sync word portion, the sync word portion forthe coherent detection. Using sync word as a part of the pilot symbolsmakes possible to prevent an increase in overhead of the coherentdetection.

[0010] In the third aspect of the present invention, there is provided amobile communication system using a digital radio communication scheme,wherein mapping, which maps into one physical channel a plurality oflogical channels for transmitting information to be broadcasted by abase station, is varied in accordance with a changing rate of data to betransmitted over each of the logical channel. Here, the mapping may becarried out by varying an occurrence rate of the logical channels. Themapping may fix a position of at least one logical channel. Theinformation to be broadcasted over the logical channels may beinformation on a reverse direction interfering power amount. Theinformation to be broadcasted over the logical channels may be controlchannel information on a contiguous cell or on a current cell. Such anarrangement enables transmission to be implemented in accordance withcharacteristics of broadcasted information, thereby implementingefficient transmission.

[0011] In the fourth aspect of the present invention, there is provideda mobile communication system using a digital radio communicationscheme, wherein a number of radio frames of a fixed duration on aphysical channel is varied in accordance with a transmission rate, theradio frames constituting a processing unit on a logical channel. Suchan arrangement makes it possible to optimize the unit to which the errordetecting code (CRC) is provided, reducing the overhead of processings.

[0012] In the fifth aspect of the present invention, there is provided amobile communication system using CDMA, the mobile communication systemuses for an inphase component and a quadrature component a same shortcode and different long codes as spreading codes. Here, the differentlong codes may have their phases shifted. This configuration preventsshort codes which are finite resources from being wasted.

[0013] In the sixth aspect of the present invention, there is provided amobile communication system employing a digital radio communicationscheme, wherein frame transmission timings on physical channels from abase station to mobile stations are delayed by random durations forrespective sectors associated with the same base station. Here, therandom durations may be assigned to respective dedicated physicalchannels at a call setup. Providing the random delay in this way makesit possible for the interfering power to be uniformly distributed alongthe time axis when there are multiple physical channels which aretransmitted intermittently, thereby reducing collision of signals.

[0014] In the seventh aspect of the present invention, there is provideda multicode transmission system in a CDMA mobile communication system,which communicates with a mobile station over a plurality of physicalchannels that use different spreading codes, the multicode transmissionsystem comprising: transmitting one or more pilot symbols and atransmission power control command through one of the, plurality ofphysical channels; and carrying out in common with the plurality ofphysical channels coherent detection using the same pilot symbols andtransmission power control in accordance with the same transmissionpower control command. Here, transmission power of a portion of thepilot symbols and the transmission power control command transmittedover the one of the plurality of physical channels may be greater thantransmission power of other data portions. Transmission power of theportion of the pilot symbols and the transmission power control commandtransmitted over the one of the plurality of physical channels may begreater than transmission power of other data portions by a factor of anumber of the multicodes.

[0015] In the eighth aspect of the present invention, there is provideda multicode transmission system in a CDMA mobile communication system,which communicates with a mobile station over a plurality of physicalchannels that use different spreading codes, the multicode transmissionsystem comprising: assigning to the plurality of physical channels sameone or more pilot symbols and a same transmission power control command;transmitting a portion of the pilot symbols and the transmission powercontrol command on the plurality of physical channels by spreading onlythat portion using a same spreading code; and carrying out in commonwith the plurality of physical channels coherent detection using thesame pilot symbols and transmission power control in accordance with thesame transmission power control command. This makes it possible toimplement efficient multicode transmission.

[0016] In the ninth aspect of the present invention, there is provided atransmission power control system in a CDMA mobile communication system,wherein a base station carries out transmission power control inaccordance with a predetermined pattern until synchronization in thebase station is established, receives, when the synchronization isestablished, a transmission power control command based on SIRmeasurement results in a mobile station, carries out transmission powercontrol in response to the transmission power control command, andtransmits a transmission power control command based on SIR measurementresults in the base station; and the mobile station carries outtransmission power control from an initial value, and transmits, afterthe synchronization has been established, the transmission power controlcommand based on the SIR measurement results in the mobile station.Here, the predetermined pattern may be a pattern for rapidly increasingtransmission power up to a predetermined value, and subsequentlygradually increasing the transmission power. The predetermined patternmay be variable in the base station. The initial value in the mobilestation may be transmitted from the base station. The base station maytransmit, before the synchronization in the base station is established,to the mobile station a transmission power control command of apredetermined second pattern; and the mobile station may controltransmission power in response to the transmission power control commandwhich is transmitted. The transmission power control command of thesecond pattern may be varied by the base station. The mobile station maycarry out, until the synchronization in the base station is established,the transmission power control in accordance with a patternpredetermined in the mobile station. Thus gradually increasing forwardtransmission power can prevent communications with other mobile stationsfrom being adversely affected. Furthermore, since the control is carriedout in two stages, the synchronization can be established quickly. Sincethe base station takes the initiative of the power control, optimumcontrol patterns can be selected. In addition, using the fixed controlpattern in the mobile station simplifies the configuration.

[0017] In the tenth aspect of the present invention, there is provided amobile communication system employing a packet digital radiocommunication scheme between a base station and mobile stations, whereinthe base station makes a decision as to whether to switch physical radiochannels to be used; and switches, if necessary, the physical radiochannels to be used, and wherein the foregoing control is carried outbetween the base station and the mobile stations without involvingconnection control of the base station with a wire section. Here, theswitching may be carried out in accordance with traffic volume betweenthe base station and the mobile stations. The physical radio channelsmay be a common physical radio channel and a plurality of dedicatedphysical radio channels. Since the switching control in accordance withthe present invention carries out the switching control based on thedecision of the base station (BTS) in this way, it does not involve theswitching control in the wire section (between the base station andcontrol center (BSC), for example). This makes it possible to reduce theload of the switching control, and to implement high speed switchingcontrol.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To further clarify the above and other advantages and features ofthe present invention, a more particular description of the inventionwill be rendered by reference to specific embodiments: thereof which areillustrated in the appended drawings. It is appreciated that thesedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting of its scope. The invention willbe described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

[0019]FIG. 1 is a block diagram showing a functional configuration of abase station in accordance with the present invention;

[0020]FIG. 2 is a diagram illustrating a structure of a logical channel;

[0021]FIG. 3 is a diagram illustrating a structure of a physicalchannel;

[0022]FIG. 4 is a diagram showing the relationship of FIGS. 4A and 4B;

[0023]FIG. 4A is a diagram illustrating signal formats of the physicalchannel;

[0024]FIG. 4B is a diagram illustrating signal formats of the physicalchannel;

[0025]FIG. 5 is a graph illustrating simulation results of thedependence of the symbol rate of 32 ksps on the number of pilot symbols;

[0026]FIG. 6 is a graph illustrating simulation results of thedependence of the symbol rate of 128 ksps on the number of pilotsymbols;

[0027]FIGS. 7A and 7B are diagrams illustrating formats of reversecommon control physical channel signals;

[0028]FIG. 8 is a diagram illustrating correspondence between physicalchannels and logical channels;

[0029]FIG. 9 is a diagram illustrating a mapping example of a logicalchannel onto a perch channel;

[0030]FIG. 10 is a diagram illustrating a PCH mapping scheme;

[0031]FIG. 11 is a diagram illustrating a FACH mapping scheme;

[0032]FIG. 12 is a diagram illustrating a mapping of DTCH and ACCH ontoa dedicated physical channel;

[0033] FIGS. 13A-13C are diagrams illustrating ACCH mapping schemes;

[0034]FIG. 14 is a diagram illustrating a method of using W bits;

[0035]FIGS. 15A and 15B are block diagrams each showing a configurationof a convolutional encoder;

[0036]FIG. 16 is a diagram illustrating an SFN (system frame number)transmission example;

[0037]FIG. 17 is a diagram illustrating a structure of SFN bits;

[0038]FIG. 18 is a block diagram showing a configuration of a forwardlong code generator;

[0039]FIG. 19 is a block diagram showing a configuration of a reverselong code generator;

[0040]FIG. 20 is a diagram illustrating a short code generating method;

[0041]FIG. 21 is a block diagram showing a configuration of a short codegenerator for a long code mask symbol;

[0042]FIG. 22 is a; block diagram showing a spreading code generatingmethod using a long code and short code;

[0043]FIG. 23 is a block diagram showing a configuration of a spreader;

[0044]FIG. 24 is a diagram illustrating a random access transmissionscheme;

[0045]FIG. 25 is a diagram illustrating an example of a multicodetransmission method;

[0046]FIG. 26 is a graph illustrating simulation results of multicodetransmission;

[0047]FIG. 27 is a diagram illustrating an example of the multicodetransmission method;

[0048]FIGS. 28A and 28B are diagrams illustrating a frame structure for1544 kbits/s used for transmitting ATM cells;

[0049]FIGS. 29A and 29B are diagrams illustrating a frame structure for6312 kbits/s used for transmitting ATM cells;

[0050]FIG. 30 is a diagram illustrating a pulse mask at an outputterminal of a 6312 kbits/s system;

[0051]FIG. 31 is,a diagram illustrating an example of a link structure(ATM connection) between a BTS and MCC;

[0052]FIG. 32 is a diagram illustrating a structure of an idle cell;

[0053]FIGS. 33A and 33B are diagrams illustrating an AAL-2 connectionconfiguration;

[0054]FIGS. 34A and 34B are diagrams illustrating AAL-5 connectionconfiguration;

[0055]FIG. 35 is a diagram illustrating an AAL-2 format;

[0056]FIG. 36 is a diagram illustrating a SAL format;

[0057]FIG. 37 is a diagram of illustrating an, AAL-5 format;

[0058]FIG. 38 is a diagram showing the relationship of FIGS. 38A and38B;

[0059]FIG. 38A is a diagram illustrating a signal format of a timingcell;

[0060]FIG. 38B is a diagram illustrating a signal format of a timingcell;

[0061]FIG. 39 is a diagram illustrating super frame positions;

[0062]FIG. 40 is a diagram illustrating transmission line estimationusing multiple pilot blocks;

[0063]FIGS. 41A and 41B are diagrams illustrating SIR based closed looptransmission power control;

[0064]FIG. 42 is a diagram illustrating transmission power controltimings;

[0065]FIG. 43 is a diagram illustrating transition to the closed looptransmission power control;

[0066]FIG. 44 is a diagram illustrating reverse transmission powercontrol during inter-cell diversity handover;

[0067]FIG. 45 is a diagram illustrating forward transmission powercontrol during inter-cell diversity handover;

[0068]FIG. 46 is a diagram showing the relationship of FIGS. 46A and46B;

[0069]FIG. 46A is a flowchart illustrating a synchronizationestablishment flow of a dedicated physical channel;

[0070]FIG. 46B is a flowchart illustrating a synchronizationestablishment flow of a dedicated physical channel;

[0071]FIG. 47 is a sequence diagram illustrating an example of aninter-cell diversity handover processing in packet transmission;

[0072]FIG. 48 is a diagram showing an example of a connectionconfiguration during an inter-sector handover in a reverse dedicatedphysical channel (UPCH);

[0073]FIG. 49 is a diagram showing an example of a connectionconfiguration during an inter-sector handover in a forward dedicatedphysical channel (UPCH);

[0074]FIG. 50 is a diagram showing an example of a connectionconfiguration during an inter-sector handover in a reverse commoncontrol physical channel (RACH);

[0075]FIG. 51 is a diagram showing an example of a connectionconfiguration during an inter-sector handover in a forward commoncontrol physical channel (FACH);

[0076]FIG. 52 is a diagram illustrating an example of a switchingsequence from a common control physical channel to a dedicated physicalchannel;

[0077]FIG. 53 is a diagram illustrating an example of a switchingsequence from a dedicated physical channel to a common control physicalchannel;

[0078]FIG. 54 is a diagram illustrating a format of a cell header;

[0079]FIG. 55 is a diagram illustrating an outline of band assurancecontrol;

[0080]FIG. 56 is a flowchart illustrating ATM cell transmission control;

[0081]FIG. 57 is a flowchart illustrating an AAL type 2 cell assemblingprocessing;

[0082] FIGS. 58A-58C are diagrams illustrating examples of celltransmission sequence data;

[0083]FIG. 59 is a diagram illustrating an example of an AAL type 5format;

[0084]FIG. 60 is a diagram illustrating an example of a SSCOP (servicespecific connection oriented protocol) sequence;

[0085]FIG. 61 is a flowchart illustrating a procedure of establishingSFN time synchronization in a BTS;

[0086]FIG. 62 is a diagram illustrating a BTSSFN clock phasecompensation value calculation method;

[0087]FIG. 63 is a flowchart illustrating a cell loss detection process;

[0088]FIG. 64 is a diagram showing the relationship of FIGS. 64A and64B,

[0089]FIG. 64A is a diagram illustrating a coding scheme of a BCCH1 orBCCH2 (16 ksps) logical channel;

[0090]FIG. 64B is a diagram illustrating a coding scheme of a BCCH1 orBCCH2 (16 ksps) logical channel;

[0091]FIGS. 65A and 65B are diagrams illustrating a coding scheme of aPCH (64 ksps) logical channel;

[0092]FIG. 66 is a diagram showing the relationship of FIGS. 66A and66B;

[0093]FIG. 66A is a diagram illustrating a coding scheme of a FACH-long(64 ksps) logical channel;

[0094]FIG. 66B is a diagram illustrating a coding scheme of a FACH-long(64 ksps) logical channel;

[0095]FIG. 67 is a diagram showing the relationship of FIGS. 67A and67B;

[0096]FIG. 67A is a diagram illustrating a coding scheme of a FACH-short(normal mode) (64 ksps) logical channel;

[0097]FIG. 67B is a diagram illustrating a coding scheme of a FACH-short(normal mode) logical channel; (64 ksps)

[0098]FIG. 68 is a diagram showing the relationship of FIGS. 68A and68B;

[0099]FIG. 68A is a diagram illustrating a coding scheme of a FACH-short(Ack mode) (64 ksps) logical channel;

[0100]FIG. 68B is a diagram illustrating a coding scheme of a FACH-short(Ack mode) (64 ksps) logical channel;

[0101]FIG. 69 is a diagram showing the relationship of FIGS. 69A and69B;

[0102]FIG. 69A is a diagram illustrating a coding scheme of a RACH-long(64 ksps) logical channel;

[0103]FIG. 69B is a diagram illustrating a coding scheme of a RACH-long(64 ksps) logical channel;

[0104]FIG. 70 is a diagram showing the relationship of FIGS. 70A and70B;

[0105]FIG. 70A is a diagram illustrating a coding scheme of a RACH-short(64 ksps) logical channel;

[0106]FIG. 70B is a diagram illustrating a coding scheme of a RACH-short(64 ksps) logical channel;

[0107]FIG. 71 is a diagram showing the relationship of FIGS. 71A and71B;

[0108]FIG. 71A is a diagram illustrating a coding scheme of an SDCCH (32ksps) logical channel;

[0109]FIG. 71B is a diagram illustrating a coding scheme of an SDCCH (32ksps) logical channel;

[0110]FIG. 72 is a diagram showing the relationship of FIGS. 72A and72B;

[0111]FIG. 72A is a diagram illustrating a coding scheme of an ACCH(32/64 ksps) logical channel;

[0112]FIG. 72B is a diagram illustrating a coding scheme of an ACCH(32/64 ksps) logical channel;

[0113]FIG. 73 is a diagram showing the relationship of FIGS. 73A and73B;

[0114]FIG. 73A is a diagram illustrating a coding scheme of an ACCH (128ksps) logical channel;

[0115]FIG. 73A is a diagram illustrating a coding scheme of an ACCH (128ksps) logical channel;

[0116]FIG. 74 is a diagram showing the relationship of FIGS. 74A and74B;

[0117]FIG. 74A is a diagram illustrating a coding scheme of an ACCH (256ksps) logical channel;

[0118]FIG. 74B is a diagram illustrating a coding scheme of an ACCH (256ksps) logical channel;

[0119]FIG. 75 is a diagram showing the relationship of FIGS. 75A and75B;

[0120]FIG. 75A is a diagram illustrating a coding scheme of a DTCH (32ksps) logical channel;

[0121]FIG. 75B is a diagram illustrating, a coding scheme of a DTCH(32ksps) logical channel;

[0122]FIG. 76 is a diagram showing the relationship of FIGS. 76A and76B;

[0123]FIG. 76A is a diagram illustrating a coding scheme of a DTCH (64ksps) logical channel;

[0124]FIG. 76B is a diagram illustrating a coding scheme of a DTCH (64ksps) logical channel;

[0125]FIG. 77 is a diagram showing the relationship of FIGS. 77A, 77Band 77C;

[0126]FIG. 77A is a diagram illustrating a coding scheme of a DTCH (128ksps) logical channel;

[0127]FIG. 77B is a diagram illustrating a coding scheme of a DTCH (128ksps) logical channel;

[0128]FIG. 77C is a diagram illustrating a coding scheme of a DTCH (128ksps) logical channel;

[0129]FIG. 78 is a diagram showing the relationship of FIGS. 78A, 78Band 78C;

[0130]FIG. 78A is a diagram illustrating a coding scheme of a DTCH (256ksps) logical channel;

[0131]FIG. 78B is a diagram illustrating a coding scheme of a DTCH (256ksps) logical channel;

[0132]FIG. 78C is a diagram illustrating a coding scheme of a DTCH (256ksps) logical channel;

[0133]FIG. 79 is a diagram showing the relationship of FIGS. 79A, 79Band 79C;

[0134]FIG. 79A is a diagram illustrating a coding scheme of a DTCH (512ksps) logical channel;

[0135]FIG. 79B is a diagram illustrating a coding scheme of a DTCH (512ksps) logical channel;

[0136]FIG. 79C is a diagram illustrating a coding scheme of a DTCH (512ksps) logical channel;

[0137]FIG. 80 is a diagram showing the relationship of FIGS. 80A, 80Band 80C;

[0138]FIG. 80A is a diagram illustrating a coding scheme of a DTCH (1024ksps) logical channel;

[0139]FIG. 80B. is a diagram illustrating a coding scheme of a DTCH(1024 ksps) logical channel;

[0140]FIG. 80C is a diagram illustrating a coding scheme of a DTCH (1024ksps) logical channel;

[0141]FIG. 81 is a diagram showing the relationship of FIGS. 81A and81B;

[0142]FIG. 81A is a diagram illustrating a coding scheme of an UPCH (32ksps) logical channel;

[0143]FIG. 81B is a diagram illustrating a coding scheme of an UPCH (32ksps) logical channel;

[0144]FIG. 82 is a diagram showing the relationship of FIGS. 82A and82B;

[0145]FIG. 82A is a diagram illustrating a coding scheme of an UPCH (64ksps) logical channel;

[0146]FIG. 82B is a diagram illustrating a coding scheme of an UPCH (64ksps) logical channel;

[0147]FIG. 83 is a diagram showing the relationship of FIGS. 83A and83B;

[0148]FIG. 83A is a diagram illustrating a coding scheme of an UPCH (128ksps) logical channel;

[0149]FIG. 83B is a diagram illustrating a coding scheme of an UPCH (128ksps) logical channel;

[0150]FIG. 84 is a diagram showing the relationship of FIGS. 84A and84B;

[0151]FIG. 84A is a diagram illustrating a coding scheme of an UPCH (256ksps) logical channel;

[0152]FIG. 84B is a diagram illustrating a coding scheme of an UPCH (256ksps) logical channel;

[0153]FIG. 85 is a diagram illustrating transmission timings of a perchchannel and common control physical channel;

[0154]FIG. 86 is a diagram illustrating transmission timings of areverse common control physical channel (RACH);

[0155]FIG. 87 is a diagram showing the relationship of FIGS. 87A and87B;

[0156]FIG. 87A is a diagram illustrating transmission and receptiontimings of a dedicated physical channel (during non-DHO);

[0157]FIG. 87B is a diagram illustrating transmission and receptiontimings of a dedicated physical channel (during non-DHO);

[0158]FIG. 88 is a diagram showing the relationship of FIGS. 88A and88B;

[0159]FIG. 88A is a diagram illustrating transmission and receptiontimings of a dedicated physical channel (during DHO);

[0160]FIG. 88B is a diagram illustrating transmission and receptiontimings of a dedicated physical channel (during DHO);

[0161]FIG. 89 is a diagram illustrating a transmission pattern of perchchannels;

[0162]FIG. 90 is a diagram showing the relationship of FIGS. 90A and90B;

[0163]FIG. 90A is a diagram illustrating a transmission pattern of aforward common control channel (for FACH);

[0164]FIG. 90B is a diagram illustrating a transmission pattern of aforward common control channel (for FACH);

[0165]FIG. 91 is a diagram illustrating a transmission pattern of aforward common control channel (for PCH);

[0166]FIG. 92 is a diagram illustrating a transmission pattern of areverse common control channel (for RACH);

[0167]FIG. 93 is a diagram illustrating a transmission pattern of adedicated physical channel (during high speed closed loop transmissionpower control);

[0168]FIG. 94 is a diagram illustrating a transmission pattern of a 32ksps dedicated physical channel (DTX control);

[0169]FIG. 95 is a diagram showing the relationship of FIGS. 95A and95B;

[0170]FIG. 95A is a flowchart illustrating a CPS PDU (content providersystem protocol data unit) assembling method (other than RACH);

[0171]FIG. 95B is a flowchart illustrating a CPS PDU (content providersystem protocol data unit) assembling method (other than RACH);

[0172]FIG. 96 is a diagrams showing the relationship of FIGS. 96A and96B;

[0173]FIG. 96A is a flowchart illustrating a CPS PDU assembling method(RACH); and

[0174]FIG. 96B is a flowchart illustrating a CPS PDU assembling method(RACH).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0175] 1. Outline of a System.

[0176] 1.1 CDMA Base Station.

[0177] A base transceiver station (BTS) in accordance with the presentinvention will now be described in detail, which carries outcommunications with mobile stations by CDMA (Code Division MultipleAccess) and with a control/switching center by ATM (AsynchronousTransfer Mode).

[0178] 1.2 Explanation of Abbreviations.

[0179] Abbreviations used in the present specification are shown inTable 1. TABLE 1 List of abbreviations No. Abbreviations Terms 1 BTSbase transceiver station 2 AMP transmitting/receiving amplifier 3 MDEbase station modulator/demodulator 4 MS radio mobile station 5 ANTantenna 6 HW wire transmission line 7 MCC mobile control/switchingcenter 8 HW-INT wire transmission path interface 9 TRX radio transceiver10 BTS-CNT base transceiver station controller 11 BB base-band signalprocessor 12 MT maintenance tool

[0180] 2. Structures

[0181] 2.1. Functional Configuration

[0182] The base station has a configuration as shown in FIG. 1. Theblock designated by the reference symbol BTS in FIG. 1 shows afunctional configuration of the base station in accordance with thepresent invention.

[0183] The following contents explain the functional structure, thoughthe present invention is not restricted by the hardware configuration.The reference symbol MCC in FIG. 1 designates control/switchingequipment for controlling the base station.

[0184] 2.2.

[0185] Table 2 shows outlines of functions of various blocks. TABLE 2Outline of functions of blocks of BTS 1 Transmitting/receiving Beingprovided with a transmitting amplifier amplifier (AMP) for amplifying atransmitted RF signal, and a low noise amplifier for amplifying areceived RF signal, duplexing the RF transmitted signal and RF receivedsignal, and connecting them to the ANT. 2 Radio stage (TRX) D/Aconverting a transmitted signal that has been subject to basebandspreading, and converting it to an RF signal by quadrature modulation,and carrying out quasi-coherent detection of a received signal fed froma receiving amplifier, A/D converting it, and transferring it to abaseband block. 3 Baseband signal Carrying out baseband processings suchas processor (BB) error correcting encoding, framing, data modulationand spreading of transmitted data, and de spreading of a receivedsignal, chip synchronization, error correcting decoding, datademultiplexing, maximal ratio combining during inter-sector diversityhandover, and the like. 4 Radio base station Exchanging a control signalwith MCC to controller (BTS-CNT) carry out management of radio channels,and establishment or release of radio channels. 5 wire transmission pathHaving an ATM processing function, and interface (HW-INT) AAL type 2 andAAL type 5 functions in an inter-office transmission path interface.Providing an SSCOP function to a control signal between MCC and BS.Generating an operation clock of a BTS from a transmission path. 6Maintenance Having a function of specifying parameters tool (MT) ofdevices, and a function of collecting data.

[0186] 3. Operation Conditions

[0187] 3.1. Initial Processing

[0188] The base station automatically resets itself when power is turnedon.

[0189] When resetting a CPU, the following processings are carried outin accordance with programs in a ROM.

[0190] (1) Internal Checking of the CPU.

[0191] (2) Start up of APs (Application Programs).

[0192] 4. Interface Conditions

[0193] 4.1. Radio Interface

[0194] 4.1.1 Major Specifics

[0195] Table 3 shows major specifics of the radio interface betweenmobile stations and the base station. TABLE 3 Major specifics of radiointerface Item Specifics Radio access scheme DS-CDMA FDD Frequency 2 GHzband Carrier frequency 5 MHz (expandable to 1.25/10/20 MHz) spacing Chiprate 4.096 Mcps (expandable to 1.024/8.192/ 16.384 Mcps) Short codelength 256-4 chip length Long code length Forward: 10 ms (Truncate 2¹⁶-1chip long Gold sequences at 10 ms). Reverse: 2¹⁶ × 10 ms (Truncate 2⁴¹ -1 chip long Gold sequences at 2¹⁶ × 10 ms). Number of 2 (select two outof four carries) switched carriers Modulation/de- Data: QPSK, pilotsymbol coherent detection, and modulation scheme RAKE. Spread: QPSK.Encoding/decoding Internal codes: Convolutional encoding scheme (R = 1/3or 1/2, K = 9) and Viterbi soft decision decoding. External codes:Reed-Solomon codes (for data transmission) Symbol rate 16-1024 kspsInformation Variable up to maximum 384 kbps transmission rate DiversityRAKE + Antenna Inter-base station Asynchronous

[0196] 4.1.2 Radio Channel Structure

[0197] 4.1.2.1 Logical Channel Structure

[0198] Structures of logical channels are illustrated in FIG. 2.

[0199] 4.1.2.1.1. Broadcast Control Channels 1 and 2 (BCCH1 and BCCH2)

[0200] Broadcast control channels (BCCHs) are a one-way channel forbroadcasting from a base station to mobile stations system controlinformation on each cell or sector. The broadcast control channeltransmits time varying information such as SFNs (System Frame Numbers),reverse interference power values, etc.

[0201] 4.1.2.1.2. Paging Channel (PCH)

[0202] A paging channel (PCH) is a one-way channel for transferring fromthe base station to mobile stations the same information all at onceover a large area. This channel is used for paging.

[0203] 4.1.2.1.3. Forward Access Channel-Long (FACH-L)

[0204] A forward access channel-long is a one-way channel fortransmitting from the base station to mobile stations controlinformation or user packet data. This channel, which is used only when anetwork knows the location cell of a mobile station, is employed totransmit rather a large amount of information.

[0205] 4.1.2.1.4. Forward Access Channel-Short (FACH-S)

[0206] A forward access channel-short is a one-way channel fortransmitting from the base station to mobile stations controlinformation or user packet data. This channel, which is used only when anetwork knows the location cell of a mobile station, is employed totransmit rather a small amount of information.

[0207] 4.1.2.1.5. Random Access Channel-Long (RACH-L)

[0208] A random access channel-long is a one-way channel fortransmitting from mobile stations to the base station controlinformation or user packet data. This channel, which is used only when amobile station knows its location cell, is employed to transmit rather alarge amount of information.

[0209] 4.1.2.1.6. Random Access Channel-Short (RACH-S)

[0210] A random access channel-short is a one-way channel fortransmitting from mobile stations to the base station controlinformation or user packet data. This channel, which is used only when amobile station knows its location cell, is employed to transmit rather asmall amount of information.

[0211] 4.1.2.1.7. Stand Alone Dedicated Control Channel (SDCCH)

[0212] A stand alone dedicated control channel is a point-to-pointtwo-way channel that transmits control information, and occupies onephysical channel.

[0213] 4.1.2.1.8. Associated Control Channel (ACCH)

[0214] An associated control channel is a point-to-point two-way channelthat transmits control information. This channel is a control channelthat is associated with a dedicated traffic channel (DTCH) which will bedescribed below.

[0215] 4.1.2.1.9. Dedicated Traffic Channel (DTCH)

[0216] A dedicated traffic channel is a point-to-point two-way channelthat transmits user information.

[0217] 4.1.2.1.10. User Packet Channel (UPCH)

[0218] A user packet channel is a point-to-point two-way channel thattransmits user packet data.

[0219] 4.1.2.2. Structure of Physical Channels

[0220]FIG. 3 illustrates structures of a physical channel, and FIGS. 4Aand 4B illustrate characteristics of individual physical channels. TABLE4 Characteristics of physical channels Common control physical DedicatedPerch Channels channel Physical Channel Symbol rate 16 kbps Reversedirection: 16/64 ksps 32/64/128/ Forward direction: 64 ksps 256/512/1024ksps Characteristics Transmission power Only radio frames High speedcontrol is not containing transmitted closed loop applied. Usually,information are sent. No transmission there are a first symbolsincluding pilot power control perch channel symbols are sent of radiocan be carried through which frames without containing out. transmissionis transmitted information. always carried out, (PD sections of PCH areand a second perch always sent). channel through High speed closed loopwhich only parts of transmission power control symbols are is notcarried out. transmitted

[0221] 4.1.2.2.1. Perch Channel

[0222] A perch channel is a physical channel whose receiving level ismeasured for selecting a cell of a mobile station. Besides, the channelis a physical channel which is initially captured when the mobilestation is turned on. The perch channel includes a first perch channeland a second perch channel: The former is spread by a short codeuniquely assigned to the system for accelerating the cell selection whenthe mobile station is turned on, and continues transmission all thetime; whereas the latter is spread by a short code corresponding to aforward long code, and transmits only part of symbols. The perch channelis a one-way physical channel from the base station to mobile stations.

[0223] The short codes used by the second perch channel differ from theshort code system employed by the other physical channels.

[0224] 4.1.2.2.2. Common Control Physical Channel

[0225] The common control physical channel is used in common by multiplemobile stations located in the same sector. The reverse common controlphysical channel is a random access channel.

[0226] 4.1.2.2.3. Dedicated Physical Channels

[0227] Dedicated physical channels are each established between a mobilestation and the base station in a point-to-point fashion.

[0228] 4.1.2.3. Signal Formats of the Physical Channels.

[0229] All the physical channels assume a three layer structure of asuper frame, radio frames and time slots. The structures of the radioframes and time slots vary (in terms of the number of pilot symbols)depending on the type of the physical channels and the symbol rate.FIGS. 4A and 4B illustrate the signal formats of channels other than thereverse common control physical channels.

[0230] Relationships between the symbol rate and the number of pilotsymbols will be described with reference to FIGS. 5 and 6.

[0231]FIGS. 5 and 6 illustrate simulation results of the effect ofvarying the number of pilot symbols for respective symbol rates:simulation results with respect to the physical channels with differentsymbol rates of 32 ksps (symbols per second) and 128 ksps, respectively.In FIGS. 5 and 6, the horizontal axis represents the number of pilotsymbols contained in each time slot (of 0.625 msec), and the verticalaxis represents a necessary Eb/Io, that is, a ratio of the requiredreceived power (Eb) per bit after the error correction to theinterference power (Io) per unit frequency band in a state that meets aquality required. The Eb is obtained by dividing the total amount ofthe. received power by the number of bits after the error correction, inthe case of which overheads such as the pilot symbols are counted aspart of the received power. The smaller the Eb/Io, the lower receivedpower can meet the required quality, which is more effective in terms ofcapacity. The required quality is set at BER (bit error rate)=10⁻³ in 32ksps physical channels considering that they are for voice transmission,whereas it is set at BER=10⁻⁶ in 128 ksps physical channels consideringthat they are for data transmission. The radio wave propagationconditions are identical in two FIGS. 5 and 6.

[0232] In either symbol rate, an optimum value of the number of pilotsymbols that can maximize the capacity is present because there is atrade-off between the degradation in the accuracy of the coherentdetection due to the reduction in the number of pilot symbols, and theincrease in the overhead due to the increase in the number of pilotsymbols. The optimum number of the pilot symbols varies depending on thesymbol rates, such as six for 32 ksps and 16 for 128 ksps. In addition,the ratio of the optimum number of the pilot symbols to the total numberof symbols also vary depending on the symbol rate such as 30% for 32ksps and 20% for 128 ksps.

[0233] Accordingly, fixedly assigning the number or ratio of the pilotsymbols will reduce the capacity at some symbol rate.

[0234] In view of the fact that the optimum number and rate of the pilotsymbols vary depending on the symbol rates, the present inventionassumes the structures as shown in FIGS. 4A and 4B.

[0235]FIGS. 7A and 7B illustrate the signal formats of the radio frameand time slots of the reverse common control physical channel, in whichthe numerals designate the number of symbols.

[0236] 4.1.2.3.1. Super Frame.

[0237] The super frame consists of 64 radio frames, and is determined onthe basis of SFN which will be described below.

[0238] The initial radio frame of the super frame: SFN mod 64=0.

[0239] The final radio frame of the super frame: SFN mod 64=63.

[0240] 4.1.2.3.2. Pilot Symbols and Sync Word (SW).

[0241] Pilot symbol patterns are shown in Table 5, in which halftoneportions represent sync words (SW) for the frame alignment. The symbolpattern of the pilot symbols other than the sync words (SW) is “11”.

[0242] As shown in Table 5, the pilot symbols are transmitted togetherwith the sync words. This makes it possible to reduce the overhead andincrease the data transmission efficiency. In addition, once the framealignment has been established, since the sync words can be consideredas an integral part of a known fixed pattern, and are utilized as thepart of the pilot symbols for the coherent detection, the accuracy ofthe coherent detection can be maintained without the slightestdegradation.

[0243] The processing on a receiving side will now be described when thesync words (SW) are transmitted with the pilot symbols.

[0244] 1. First, chip synchronization is acquired by searching for a despreading timing that provides a maximum correlation value by carryingout despreading processings at multiple timings. Subsequently,despreading is carried out in accordance with the acquired timing.

[0245] 2. An amount of phase rotation is estimated using pilot symbols(other than the sync word (SW)) with a fixed pattern, followed by thecoherent detection using the estimated amount for demodulating the syncword (SW). The demodulation scheme involving the estimation of the phaserotation magnitude is disclosed in Japanese Patent Application Laid-openNo. 6-140569 (1994), “Coherent detector”, and is incorporated here byreference.

[0246] 3. Frame alignment is established using the demodulated sync word(SW). More specifically, the extent is examined to which the bitsequence of the demodulated sync word (SW) matches the predeterminedpatterns, and the most likely bit sequence is decided considering thebit error rate.

[0247] 4. Once the frame alignment has been established, the bitsequence of the sync word (SW) is obvious, and hence can be handled inthe same manner as the fixed pattern of the pilot symbols. Thus, thesync word (SW) can be used as an integral part of the pilot symbols toestimate the phase rotation amount and demodulate the data portion bythe coherent detection. TABLE 5 Pilot Symbol Patterns Pilot SymbolPatterns 16 ksps 256, 512, 1024 ksps dedicated common control Pilot slotphysical channel physical channel Others number 0 1 2 3 4 5 6 7 0 1 2 30 1 2 3 slot #1 11 11 11 11 11 11 11 10 11 11 11 11 11 11 11 11 slot #211 10 11 10 11 10 11 01 11 10 11 01 11 11 11 01 Slot #3 11 10 11 01 1111 11 01 11 10 11 10 11 01 11 01 Slot #4 11 11 11 01 11 00 11 10 11 0111 00 11 10 11 01 Slot #5 11 11 11 00 11 01 11 10 11 00 11 10 11 10 1111 Slot #6 11 11 11 11 11 01 11 10 11 10 11 11 11 10 11 11 Slot #7 11 1011 11 11 01 11 10 11 10 11 11 11 01 11 00 Slot #8 11 01 11 00 11 10 1100 11 00 11 00 11 10 11 01 Slot #9 11 11 11 10 11 00 11 01 — 11 11 11 00Slot #10 11 01 11 11 11 11 11 00 — 11 01 11 01 Slot #11 11 10 11 10 1111 11 10 — 11 11 11 10 Slot #12 11 01 11 10 11 10 11 00 — 11 01 11 01Slot #13 11 10 11 01 11 11 11 10 — 11 00 11 01 Slot #14 11 00 11 10 1110 11 00 — 11 10 11 00 Slot #15 11 01 11 10 11 00 11 00 — 11 01 11 00Slot #16 11 10 11 00 11 00 11 00 — 11 00 11 00

[0248] In Table 5, each bit is transmitted in the order of “I” and “Q”from the left-hand side to the right-hand side.

[0249] In the forward common control physical channels, burst modetransmission of a radio frame length can take place, in which case, thepilot symbols are added at the final position of the bursts. The numberof symbols and the symbol pattern to be added is the slot #1 pattern ofTable 5.

[0250] In the reverse common control physical channels, one radio frameforms one burst, and the pilot symbols are added at the final positionof the radio frame. The number of symbols and the symbol pattern to beadded is the slot #1 pattern of Table 5.

[0251] 4.1.2.3.3. TPC Symbol.

[0252] The relationships between transmission power control (TPC) symbolpatterns and transmission power control amounts are shown in Table 6.TABLE 6 TPC symbol patterns. TPC Symbol Transmission power controlamount 11 +1.0 dB 00 −1.0 dB

[0253] 4.1.2.3.4. Long Code Mask Symbol.

[0254] A long code mask symbol is spread by a short code only withoutusing any long code.

[0255] Although symbols of the perch channels other than the long codemask symbol use the short codes in layered orthogonal code sequences asshown in FIG. 20, the long code mask symbol is spread using the shortcode selected from the orthogonal Gold sequences with a code length of256. Details concerning this will be described in 4.1.4.1.3. The longcode mask symbol is contained one symbol per slot in the first andsecond perch channels, and the symbol pattern thereof is “11”. The perchchannels use two spreading codes to transmit their long code masksymbols individually. In particular, the second perch channel transmitsonly the long code mask symbol without transmitting any other symbol.

[0256] 4.1.2.4. Mapping of the Logical Channels onto the PhysicalChannels.

[0257]FIG. 8 illustrates the relationships between the physical channelsand the logical channels that are mapped onto the physical channels.

[0258] 4.1.2.4.1. Perch Channels.

[0259]FIG. 9 illustrates a mapping example of the logical channel ontothe perch channel.

[0260] Only BCCH1 and BCCH2 are mapped.

[0261] Onto the initial position of the super frame, BCCH1 is mappedwithout exception.

[0262] With respect to the mapping other than the mapping of the BCCH1into the initial position of the super frame, either BCCH1 or BCCH2 ismapped in accordance with structure information designated.

[0263] The BCCH1 and BCCH2 are each transmitted in every 2×Nconsecutive. radio frames so that two radio frames constitute one radiounit, and transmit one layer 3 message. The layer 3 message transmittedthrough the BCCH1 and BCCH2 do not overlay two or more super frames.

[0264] The BCCH1 and BCCH2 each transmit in each radio unit thefollowing information, for example, which is generated by the BTS.

[0265] SFN (System Frame Number).

[0266] Reverse interfering power amount.

[0267] The reverse interfering power amount is a time-varying latestresult measured by the BTS. The information BCCH1 and BCCH2 transmit canhave different characteristics. For example, BCCH1 can transmittime-fixed information, whereas BCCH2 can transmit time-varyinginformation. In this case, the time-varying information can betransmitted efficiently by reducing the occurrence frequency of theBCCH1 and increasing that of the BCCH2. The occurrence frequencies ofthe BCCH1 and BCCH2 can be determined considering the frequency ofchanges in the information. It is also possible to dispose the BCCH1 atfixed positions of the super frame, such as the initial and centralpositions, for example, and places BCCH2 at the remaining positions. Asan example of time-fixed information, there are code numbers of controlchannels of contiguous cells or the present cell. The above-mentionedreverse interfering power amount is time-varying information.

[0268] Although the foregoing description is provided in an exampleincluding two broadcast control channels (BCCH1 and BCCH2), three ormore broadcast control channels can be provided. These multiplebroadcast control channels can be transmitted with varying theiroccurrence frequencies.

[0269] 4.1.2.4.2. Common Control Physical Channel.

[0270] Only PCH and FACHs are mapped into the forward common controlphysical channel. RACHs are mapped into the reverse common controlphysical channel. Either FACHs or PCHs are mapped into a single forwardcommon control physical channel. Whether the logical channel to bemapped into the single forward common control physical channel is PCH orFACH is determined for each common control physical channel established.One forward common control physical channel into which the FACHs aremapped is paired with one reverse common control physical channel. Thepair is designated by a pair of spreading codes. The designation of thepair is in terms of the physical channel, in which the sizes (S/L) ofthe FACH and RACH are not defined. As the FACH a mobile station receivesand the RACH it transmits, a pair of the FACH and RACH is used on thepair of the forward common control physical channel and reverse commoncontrol physical channel, respectively. In addition, in an Acktransmission processing by the BTS for the received RACH, which will bedescribed later, the Ack is transmitted through the FACH-S on theforward common control physical channel which is paired with the reversecommon control physical channel through which the received RACH istransmitted.

[0271] 4.1.2.4.2.1. A Mapping Method of PCHs into the Common ControlPhysical Channel.

[0272]FIG. 10 illustrates a mapping method of the PCHs. The PCHs areeach divided into a plurality of groups in a super frame, and each grouptransmits the layer 3 information. The number of groups per commoncontrol physical channel is 256. Each group of the PCHs containsinformation of an amount of four time slots, and consists of sixinformation portions: two portions are for incoming call presence andabsence indicators (PD portions), and the remaining four portions arefor called user identification number portions (I portions). The PDportions are transmitted prior to the I portions in each group.

[0273] The six information portions are assigned to over 24 time slotsin a predetermined pattern in all the groups. The pattern over the 24time slots are shifted every four slot interval so as to dispose theplurality of groups onto the single common control physical channel. Thefirst PCH is disposed such that the initial symbols of the PD portion ofthe first PCH becomes the initial symbols of the super frame. Thesections of PCHs in each group are disposed in the PCH radio frames suchthat they are shifted every four time slot interval in the order of thesecond group, third group, etc. The final one of the groups overlays thetwo super frames.

[0274] 4.1.2.4.2.2. Mapping Method of the FACH onto the Common ControlPhysical Channel.

[0275]FIG. 11 shows a mapping example of the FACH. Any FACH radio frameon a common control physical channel can be used as either a logicalchannel FACH-L or FACH-S. The logical channel that receives atransmission request first is transmitted by the FACH radio frame. Ifthe length of the information to be transmitted by the FACH is longerthan a predetermined value, FACH-L is used, and otherwise FACH-S isused. With respect to FACH-S, four FACH-S'es are time multiplexed intoone FACH radio frame to be transmitted.

[0276] Each of the four FACH-S'es consists of four time slots, and isdisposed in one radio frame at every four time slot interval, withshifting one slot for each FACH-S. Thus, the time slots assigned to thefour FACH-S'es are as follows.

[0277] First FACH-S: First, fifth, ninth and 13^(th) time slots.

[0278] Second FACH-S: Second, sixth, 10^(th) and 14^(th) time slots.

[0279] Third FACH-S: Third, seventh, 11^(th) and 15^(th) time slots.

[0280] Four FACH-S: Fourth, eighth, 12^(th) and 16^(th) time slots.

[0281] If the first logical channel that receives the transmissionrequest is a FACH-S, other FACH-S'es that are stored in a buffer at thattime can be transmitted up to four with time multiplexing them into oneFACH radio frame. In this case, even if a FACH-L has been stored by thattime, FACH-S'es that receive a transmission request later than thatFACHL can be multiplexed and transmitted.

[0282] A mobile station can simultaneously receive the entire FACH-S'esand FACH-L on each common control physical channel. It is sufficient fora mobile station to receive one common control physical channel even inthe case where a base station transmits a plurality of common controlphysical channels for transmitting FACHs. Which one of them is to bereceived by the mobile station is determined between the mobile stationand the BTS.

[0283] The FACH-S has two modes of transmission format. One is a format(layer 3 transmission mode) for transmitting information of layer 3 andhigher order which is designated. The other one is a format (ACK mode)for transmitting an ACK of receiving a RACH.

[0284] An ACK mode FACH-S can contain ACKs to up to seven mobilestations at the maximum. An ACK mode FACH-S is always transmitted as thefirst FACH-S. An ACK mode FACH-S is transmitted at first, even if thetransmission request is received after other FACH's.

[0285] If an information volume of a higher rank information form (CPS:content provider system) that is transmitted by FACH radio units amountsto a plurality of FACH radio units, a continuous transmission isguaranteed. No other CPS is allowed to intrude into the transmission.Even the ACK mode FACH-S, which is given top priority as describedabove, is not allowed to intrude to be transmitted.

[0286] When one CPS is transmitted with a plurality of FACH radio units,either FACH-L's or FACH-S'es are used, without being used in a mixedmanner. When one CPS is transmitted continuously with a plurality ofFACH-S radio units, the (n+1)-th FACH-S radio unit follows the n-thFACH-S radio unit, except that it is the first FACH-S radio unit thatfollows the fourth FACH-S radio unit.

[0287] 4.1.2.4.2.3. A Mapping Method of a RACH onto a Common ControlPhysical Channel.

[0288] A RACH-S is mapped onto a 16 ksps reverse common control physicalchannel, and a RACH-L is mapped onto a 64 ksps reverse common controlphysical channel. Both the RACH-S and RACH-L consist of one radio frameof 10 ms long. When they are transmitted through wireless sections, fourpilot symbols are added to the final position of the radio frame.

[0289] When transmitting the RACH, a mobile station uses the RACH-L orRACH-S freely in accordance with a transmission information volume.Receiving the RACH-L or RACH-S normally, a base station transmits Ack tothe mobile station through a FACH. The RACH and its associated FACH thattransmits the Ack are designated by assigning the same RL-ID to both thechannels.

[0290] The frame timing for transmitting the RACH from the mobilestation is delayed by a predetermined offset from the frame timing ofthe common control physical channel onto which the FACH for transmittingthe Ack is mapped. The offset can take 16 values, one of which themobile station ramdomly selects to send the RACH.

[0291] The base station must have the function of receiving the RACH-Land RACH-S at all the offset timings.

[0292] 4.1.2.4.3. Dedicated Physical Channel.

[0293] The SDCCH and UPCH each occupy one dedicated physical channel.With regard to 32-256 ksps dedicated physical channels, a DTCH and anACCH are time multiplexed to share the same dedicated physical channel.With regard to 512 ksps and 1024 ksps dedicated physical channels, onlya DTCH occupies the dedicated physical channel without multiplexing anACCH.

[0294] The time multiplexing of the DTCH and ACCH is carried out foreach time slot by dividing logical channel symbols in the time slot andassigning them to the two channels. The ratio of the division variesdepending on the symbol rate of the dedicated physical channel. FIG. 12illustrates a mapping method of the DTCH and ACCH onto the dedicatedphysical channel.

[0295] The number of radio frames constituting a radio unit of the ACCHvaries depending on the symbol rate of a dedicated physical channel. Theradio unit of the ACCH is allocated in synchronism with a super framesuch that it is divided in accordance with the number of the time slotsand its divisions are allocated to the entire time slots over one ormore radio frames.

[0296] FIGS. 13A-13C each illustrate a mapping method of the ACCH onto asuper frame of the dedicated physical channel for each symbol rate. Onereason why the number of the radio frames constituting the radio unitvaries depending on the symbol rates is that an error correcting code(CRC) is added to each radio unit to detect and correct errors in eachunit, and hence increasing the number of the radio unit will lead to,increase the overhead of the error correcting processing (concerning thecoding processing of the ACCH, refer to FIGS. 72-74). Another reason isthat if the number of the radio units per super frame is increased inthe case where the symbol rate is low, the ratio of the error correctingcode increases, reducing the volume of the substantially transmittedinformation.

[0297] In multicode transmission, the ACCH radio unit does not overlaytwo or more physical channels, but is transmitted using a particular onecode (physical channel). The particular one code is predetermined.

[0298] 4.1.2.5. Logical Channel Coding

[0299] FIGS. 64-84 illustrate coding processings of logical channels,which are carried out in a base station (BTS).

[0300] 4.1.2.5.1. Error Detecting Code (CRC).

[0301] An error detecting code (CRC) is added to each CPSPDU (commonpart sublayer protocol data unit), each internal encoding unit, or eachselection combining unit.

[0302] 4.1.2.5.1.1. Generator Polynomials

[0303] (1)16-bit CRC

[0304] Application: CPSPDU of the entire logical channels except for theDTCH and PCH; internal encoding unit of UPCHs at all the symbol rates;selection combining unit of the 32 ksps DTCH; and an internal encodingunit of the SDCCH, FACH-S/L or RACH-S/L.

[0305] Generator polynomial: GCRC16 (X)=X¹⁶+X¹²+X⁵+1

[0306] 2) 14-bit CRC

[0307] Application: ACCHs at all the symbol rates.

[0308] Generator polynomial: GCRC14 (X)=X¹⁴+X¹³+X⁵+X³+X²+1

[0309] (3) 13-bit CRC

[0310] Application: Selection combining units of 64/128/256 ksps DTCHs.

[0311] Generator polynomial: GCRC13 (X)=X¹³+X¹²+X⁷+X⁶+X⁵+X⁴+X²+1

[0312] (4) 8-bit CRC

[0313] Application: CPSPDU of PCH.

[0314] Generator polynomial: GCRC8 (X)=X⁸+X⁷+X²+1

[0315] 4.1.2.5.1.2. CRC Calculation Application Range.

[0316] CRC for each CPSPDU: Entire CPSPDU.

[0317] CRC for each ACCH/DTCH selection combining unit: Entire unitexcept for tail bits.

[0318] CRC for each SDCCH/FACH/RACH/UPCH internal encoding unit: Entireunit except for tail bits.

[0319] FIGS. 64-84 illustrate by shaded portions the CRC calculationapplication range and CRC bits.

[0320] 4.1.2.5.1.3. Uses of CRC Check Results.

[0321] CRC for each CPSPDU: Making a decision as to whether to carry outretransmission according to a retransmission protocol of a higher layer(SSCOP, layer 3 retransmission).

[0322] CRC for each ACCH/DTCH selection combining unit: (i) outer-looptransmission power control; (ii) selection combining reliabilityinformation.

[0323] CRC for each UPCH internal encoding unit: outer-loop transmissionpower control.

[0324] CRC for each RACH internal encoding unit: layer 1 retransmission.

[0325] CRC for each SDCCH internal encoding unit: (i) outer-looptransmission power control; (ii) making a decision on the necessity forwire transmission.

[0326] 4.1.2.5.1.4. Initialization of CRC

[0327] The initial value of a CRC calculator is “all 0's”.

[0328] 4.1.2.5.2. PAD.

[0329] Application: The CPSPDU of the logical channels except for DTCHs.

[0330] A PAD is used for aligning the length of the CPSPDU with theinteger multiple of the internal encoding unit length or selectioncombining unit length. The PAD is contained in the CPSPDU by 1 oct.unit. The bits of the PAD is “all 0's”.

[0331] 4.1.2.5.3. Length

[0332] Application: The CPSPDU of logical channels except for DTCHs.

[0333] Length shows an information volume (the number of octets) of thepadding in the CPSPDU.

[0334] 4.1.2.5.4. W Bits

[0335] W bits indicates the initial, continuous, or final position ofthe CPSPDU for each internal encoding unit (for each selection combiningunit in the case of an ACCH). The relationships between the bit patternsof the W bits and their indications are shown in Table 7, and the usesthereof is shown in FIG. 14.

[0336] A flowchart illustrating an assembling process of the CPSPDUusing the W bits is shown in FIGS. 95A to 96B. TABLE 7 W bit pattern Wbits Designated contents 00 continue & continue 01 continue & end 10start & continue 11 start & end

[0337] 4.1.2.5.5. Internal Code.

[0338] An internal code is one of the convolutional coding. FIGS. 15Aand 15B each shows a convolutional encoder.

[0339] Features of internal encoding for respective logical channels areshown in Table 8. The output of the convolutional encoder is produced inthe order of output 0, output 1 and output 2 (coding rate of ½ isapplied to up to output 1). The initial value of the shift register ofthe encoder is “all 0's”. TABLE 8 Features of internal encoding. Numberof Types of logical Constraint Encoding Depth of slots/radio channelslength rate Interleaving unit BCCH 1 9 1/2 10 32 BCCH 2 10 32 PCH 16 4FACH-L 72 16 FACH-S 72 4 (4 slot interval) FACH-L 72 16 FACH-S 32 8SDCCH 30 16 ACCH (32/64 ksps) 1/3 6 64 ACCH (128 ksps) 10 32 ACCH (256ksps) 24 16 DTCH (32 ksps) 24 16 DTCH (64 ksps) 64 16 DTCH (128 ksps)140 16 DTCH (256 ksps) 278 16 DTCH (512 ksps) 622 16 DTCH (1024 ksps)1262 16 UPCH (32 ksps) 1/3 30 16 UPCH (64 ksps) 70 16 UPCH (128 ksps)150 16 UPCH (256 ksps) 302 16

[0340] 4.1.2.5.6. External Encoding

[0341] (1) Reed-Solomon encoding/decoding.

[0342] Code form: An abbreviated code RS(36, 32) derived from aprimitive code RS(255, 251) defined over a Galois field GF(28).

[0343] primitive polynomial: p=X⁸+X⁷+X²+X+1.

[0344] Code generator polynomial: G(x)=(x+α¹²⁰)(x+α¹²¹)(x+α¹²²)(x+α¹²³)

[0345] An external encoding is applied only when unrestricted digitaltransmission in a circuit switching mode is carried out. The externalencoding is carried out every 64 kbps (1B) interval independently of thetransmission rate.

[0346] (2) Symbol interleaving.

[0347] Interleaving is carried out on an 8-bit symbol unit basis. Thedepth of the interleaving is 36 symbols independently of the symbol rateof the DTCH.

[0348] (3) External code handling alignment.

[0349] Each external code handling unit consists of 80 ms long data. Theexternal code handling is processed in synchronism with radio frames.The radio frames in the external code handling unit, are provided withsequence numbers 0-7 in the order of transmission. The external codehandling alignment is established in accordance with the sequencenumbers. The number of alignment guard stages are as follows(default=2). The number of forward guard stages: NF (default=2). Thenumber of backward. guard stages: NR (default=2).

[0350] 4.1.2.5.7. Reverse Link Interfering Amount.

[0351] It is reported through the BCCH1 and BCCH2. It is the latestmeasured value of the reverse interfering amount (total received powerincluding thermal noise) for each sector. A measuring method is definedby measurement parameters. Table 9 shows an example of correspondencebetween bit values and reverse interfering amounts. The bits aretransmitted from the leftmost bit in the table. The bits takes an idlepattern (see, 4.1.10) when the start of the measurement is notdesignated. TABLE 9 Correspondence of the bit values to the reverseinterfering amounts. Bit values Reverse interfering amounts 11 1111equal or greater than −143.0 dBm/Hz 11 1110 equal or greater than −143.5dBm/Hz . less than −143.0 dBm/Hz . . . . . . 00 0001 equal or greaterthan −174.0 dBm/Hz less than −173.5 dBm/Hz 00 0000 less than −174.0dBm/Hz

[0352] 4.1.2.5.8. SFN (System Frame Number)

[0353] System frame number (SFN) is reported through the BCCHI andBCCH2. The SFN has a one-to-one correspondence with the radio frame, andis incremented by one for each 10 msec long radio frame. The SFN of thefirst one of the two radio frames at each transmission timing of theBCCH1 or BCCH2 is transmitted over the BCCH1 or BCCH2. FIG. 16illustrates a transmission example of the SFN.

[0354] The base station generates counter values based on the timingsdesignated by transmission paths. The range of the SFN: 0−2¹⁶−1. Theradio frame with SFN=2¹⁶−1 is followed by the radio frame with SFN=O.

[0355] Bit arrangement: FIG. 17 shows the bit arrangement of the SFN.The bits are transmitted from the MSB of this figure.

[0356] Uses of the SFN.

[0357] (1) For calculating the phase of a reverse link long code: Thereverse link long code phase at the originating/terminating connectionand at the diversity handover is calculated as will be described in4.1.3 and illustrated in FIGS. 85-88 to generate a long code.

[0358] (2) For establishing super frame alignment: The radio frame withthe SFN of mod 64=0 is the initial frame in a super frame, and the radioframe with the SFN of mod 64=63 is the final frame in the super frame.

[0359] 4.1.2.5.9. Transmission Power.

[0360] Transmission power is broadcasted over the BCCH1 and BCCH2.Transmission power of the perch channel is notified. Range of the value:6 dBm-43 dBm. Bit arrangement: 6-bit binary notation of a valueexpressed in dBm unit (for example, 6 dBm is represented as “000110”).The bits are transmitted from the MSB.

[0361] 4.1.2.5.10. PID (Packet ID).

[0362] Application: RACH-S/L; FACH-S/L. A PID is an identifier foridentifying, on a common control physical channel, a call or a mobilestation, which is associated with transmitted information. Informationlength: 16 bits. The PID value on a FACH is designated together with itstransmitted information. The PID value transmitted over the RACH isnotified along with the transmitted information.

[0363] Uses The major uses of the PID are as follows.

[0364] (i) For sending a request for establishing the SDCCH, and forsending an establishment response. The PID is used for sending from amobile station to the BTS through the RACH a request for establishingthe SDCCH, and from the BTS to the mobile station through the FACH anestablishment response. The PID on the FACH that transmits theestablishment response is identical to the PID on the RACH that sendsthe establishment request. The PID value for this purpose is randomlyselected by the mobile station.

[0365] (ii) For carrying out packet transmission. The PID is used forthe packet data transmission on the RACH and FACH. The PID value forthis purpose is determined by the base station that selects a uniquevalue for each sector. A range of the PID value: A range over 16 bits isdivided into two parts which are used for the foregoing purposes. Table10 shows an example of the ranges for the uses. Bit structure: PIDvalues (0-65535) are represented by the 16-bit binary notation. The bitsare transmitted from the MSB. TABLE 10 Range of PID values. Uses Rangeof Values SDCCH establishment request  0 to 63 immediately before SDCCHestablishment and establishment response Packet transmission 64 to 65535

[0366] 4.1.2.5.11. Mo.

[0367] Mo is a bit for identifying the mode of the FACH-S. An example ofits bit structure is shown in Table 11. TABLE 11 Bit Structure of Mo.Bit Identification Content 0 Normal mode 1 Ack mode

[0368] 4.1.2.5.1.2. U/C.

[0369] Application: RACH-S/L, FACH-S/L and UPCHs of all the symbolrates. The U/C bit is an identifier for identifying whether theinformation conveyed by the CPSSDU (content provider system service dataunit) is user information or control information. An example of its bitstructure is shown in Table 12. TABLE 12 Structure of U/C bit BitIdentification Content 0 User Information 1 Control Information

[0370] 4.1.2.5.13. TN (Termination Node Information)

[0371] Application: RACH-S/L, FACH-S/L and UPCHs of all the symbolrates. The TN bit is an identifier for identifying a base station sideterminal node of the information conveyed by the CPSSDU. An example ofits bit structure is shown in Table 13 TABLE 13 Structure of TN bitIdentification Content Bit RACH, Reverse UPCH FACH, Forward UPCH 0 MCCTermination Transmission from MCC 1 BTS Termination Transmission fromBTS

[0372] 4.1.2.5.14. Sequence Number (S Bits).

[0373] Application: RACH. The sequence number is for achieving highlyefficient assembling of CPS considering retransmission (layer 1retransmission) over the RACH between the MS and BTX. A range, of thesequence number: 0 to 15. A CPS is assembled on the basis of thesequence number and the CRC check result. The sequence number is “0” inthe first radio unit of the CPSPDU. FIGS. 96A and 96B illustrate aflowchart of an assembling method of CPSPDU of a RACH using W bits and Sbits.

[0374] 4.1.2.5.15 PD Portion.

[0375] The PD portion includes PD1 and PD2, both of which can be used inthe same manner. The PD portion is an identifier for instructing amobile station about the presence and absence of incoming callinformation, and the necessity of receiving the BCCH. Transmitting thePD1 and PD2 at different timings enables the mobile station to improvethe reception quality owing to the time diversity effect. An example ofthe bit arrangement is shown in Table 14. TABLE 14 Bit structure of PDportion. Bits Identification Contents all 0's Incoming call informationis absent and BCCH reception is unnecessary all 1's Incoming callinformation is present and BCCH reception is necessary

[0376] 4.1.2.5;16. Maximum Length of CPSSDU.

[0377] The maximum length of the CPSSDU is LCPS regardless of the typesof the logical channels. The LCPS is set as one of the systemparameters.

[0378] 4.1.3. Transmitting and Receiving Timings of the Base Station.

[0379] FIGS. 85-88 illustrate concrete examples of the transmitting andreceiving timings of radio frames along with long code phases for eachphysical channel, when the chip rate is 4.096 Mcps. The BTS generates areference frame timing (BTS reference SFN) from a transmission path. Thetransmitting and receiving timings of various physical channels areestablished as timings that are offset from the BTS reference SFN.Table. 15 shows the offset values of the radio frame transmitting andreceiving timings of the physical channels. The BTS reference long codephase is determined such that the long code phase becomes zero at thefirst chip of the frame whose timing corresponds to BTS reference SFN=0.The long code phase of various physical channels are established atphases. The offset values of the long code phases of the physicalchannels are also shown in Table 15. TABLE 15 Offset values (in terms ofchips) of transmitting and receiving timings of physical channelsPhysical Transmitting and receiving timings Channels of radio framesLong code phases Perch channel T_(SECT) T_(SECT) Forward T_(SECT) +T_(CCCH) T_(SECT) common control physical Forward T_(SECT) + T_(FRAME) +T_(SLOT) T_(SECT) dedicated physical channel (during non-DHO) ForwardT_(SECT) + <T_(DHO)>^(*1) − 320 × C^(*2) T_(SECT) dedicated physicalchannel (during DHO) Reverse (1) T_(SECT) + T_(CCCH) (1) T_(SECT) +T_(CCCH) common control (2) T_(SECT) + T_(CCCH) + 2560 × C (2)T_(SECT) + T_(CCCH) + 2560 × C physical (3) T_(SECT) + T_(CCCH) + 5120 ×C (3) T_(SECT) + T_(CCCH) + 5120 × C channel . . (RACH) . . . . (16)T_(SECT) + T_(CCCH) + 7680 × C (16) T_(SECT) + T_(CCCH) + 7680 × CReverse T_(SECT) + T_(FRAME) + T_(SLOT) + 320 × C T_(SECT) dedicatedphysical channel (during non-DHO) Reverse T_(SECT) + T_(DHO) T_(SECT) +T_(DHO) − T_(FRAME) − T_(SLOT) − 320 × C dedicated physical channel(during DHO)

[0380] Although the physical channels other than the perch channel arenot provided with the SFN, all the physical channels consider the framenumber (FN) corresponding to the SFN of the perch channel. The FN, whichis not present physically in a transmitted signal, is generated in amobile station and the base station for respective physical channels inaccordance with the predetermined correspondence with the SFN of theperch channel. The correspondence between the SFN and FN are also shownin FIGS. 85-88.

[0381] The offset values T_(SECT), T_(DHO), T_(CCCH), T_(FRAME) andT_(SLOT) will be described here.

[0382] T_(SECT)

[0383] Offset values T_(SECT)S vary from sector to sector. (Althoughthey are synchronized between sectors within the base station, they areasynchronous between base stations). Each T_(SECT) is applied to all thephysical channels in the sector. The range of their values, which arerepresented in terms of chips, is within a slot interval. The long codephases of the forward dedicated physical channels are all aligned withthe offset values T_(SECT)S in order to reduce the interfering amountdue to forward link orthgonalization. A mobile station can recognize, ifit receives the long code mask symbol, the long code phase(corresponding to T_(SECT)), and hence can carry out transmission andreception using it. Varying the offset values T_(SECT)S between thesectors makes it possible to prevent the long code mask symbols fromtaking place at the same timing, thereby enabling each mobile station toselect its cell appropriately.

[0384] 15

[0385] T_(CCCH)

[0386] Each T_(CCCH) is an offset value for a radio frame timing of thecommon control physical channel. It can be set for each common controlphysical channel. This serves to reduce the occurrence frequency of thematching of transmission patterns between a plurality of common controlphysical channels in the same sector, thereby making uniform the forwarddirection interfering amount. The range of its value, which isrepresented in terms of symbols, is within the slot interval. Althoughits value is designated in terms of chips, the value is round down to asymbol unit of the common control physical channel to be used for theoffset.

[0387] T_(FRAME)

[0388] The T_(FRAME) is an offset value for the radio frame timing ofthe dedicated physical channel. It can be set separately for eachdedicated physical channel. The base station determines the T_(FRAME) ata call setup, and notifies the mobile station of it. The reverse linktransmission is also carried out using this offset value. Because allthe processings in the base station is carried out in synchronism withthe offset value, there occurs no delay in the processings. It servesfor the purpose of making uniform (random) the transmission traffic,thereby improving the efficiency of wire ATM transmission. Its value isrepresented in terms of slots (0.625 ms), and its range is within oneradio frame.

[0389] T_(SLOT)

[0390] The T_(SLOT) is an offset value for the radio frame timing of thededicated physical channel. It can be set separately for each dedicatedphysical channel. It serves to prevent the transmission patternmatching, and thereby making the interference uniform. The range of itsvalue which is represented in terms of symbols is within the slotinterval. Although its value is designated in terms of chips, the valueis round down to a symbol unit of the common control physical channel,and the rounded down value is used for the offset.

[0391] T_(DHO)

[0392] The T_(DHO) is an offset value for the radio frame timing of thededicated physical channel and for the reverse link long code phase. Itcorresponds to a measured value by a mobile station of the timingdifference between the reverse direction transmitting timing of themobile station and the received timing by the mobile station of theperch channel of the DHO destination station. The range of its valuewhich is represented in terms of chips is within the reverse long codephase range (0-2¹⁶−1). Although in the base station (BTS) the receivedtimings of the reverse physical channels approximately agree with thoseof Table 15, they actually fluctuate owing to propagation delay betweenthe mobile stations and the base station and to the variations of thepropagation delays. The base station (BTS) receives with canceling thesefluctuations by means of buffers or the like. The radio frame timing ofthe dedicated physical channel of a reverse link is delayed by half aslot interval as compared with that of a forward link. Thus, the delayof the transmission power control becomes one slot interval, therebyreducing control errors. More specific setting scheme of the timingdifferences are illustrated in FIGS. 85-88.

[0393] With regard to the reverse common control physical channel(RACH), the radio frame timing of the RACH is offset from that of thecorresponding forward common control physical channel. The offset valuehas four steps at time slot intervals. The initial position of a radioframe is aligned with the initial value of the long code phase. Thus,the long code phase has four offset values, as well. A mobile stationcan transmit by selecting anyone of the four offset timings. The BTS canalways receive the RACHs simultaneously which are transmitted at all theoffset timings.

[0394] 4.1.4. Spreading Code.

[0395] 4.1.4.1. Generating Method.

[0396] 4.1.4.1.1. Forward Long Code.

[0397] A forward long code consists of the Gold codes using M sequencesobtained from the following generator polynomials.

[0398] (Shift register 1) X¹⁸+X⁷+1

[0399] (Shift register 2) X¹⁸+X¹⁰+X⁷+X⁵+1

[0400] A configuration of a forward long code generator is shown in FIG.18. The initial state of a long code number value is defined as a statein which the value of the shift register 1 represents that long codenumber, and the value of the shift register 2 is set at “all 1's”. Thus,the range of the long code number is from 00000h through 3FFFFh. The MSBof the long code number is first input to the leftmost bit of the shiftregister 1 of the generator of FIG. 18.

[0401] The forward long code has a period of one radio frame interval.Accordingly, the output of the long code generator is truncated at 10 msso that it repeats the pattern from phase 0 to the phase correspondingto 10 ms. Thus, the range of the phase varies as shown in Table 16 inaccordance with the chip rate.

[0402] In addition, as will be described later in 4.1.5.3., the phase ofthe inphase component of the long code is shifted from that of thequadrature component by an amount of “shift”, which makes it possible todifferentiate the inphase component from the quadrature component. Table16 shows the phases of the two components when the “shift” is set at1024. The long code generator can implement a state in which its phaseis shifted from the initial state by an amount of any integer multipleof a clock period. TABLE 16 Correspondence between chip rates and rangesof the phase of a forward long code. Ranges of the phase (chips) Chiprates (Mcps) In phase component Quadrature 1.024 0 through 10239 1024through 11263 4.096 0 through 40959 1024 through 41983 8.192 0 through81919 1024 through 82943 16.384 0 through 163839 1024 through 164863

[0403] 4.1.4.1.2. Reverse Long Code.

[0404] A reverse long code is one of the Gold codes using M sequencesobtained from the following generator polynomials.

[0405] (Shift register 1) X⁴¹+X³+1

[0406] (Shift register 2) X⁴¹+X²⁰+1

[0407] A configuration of a reverse long code generator is shown in FIG.19.

[0408] The initial state of a long code number is defined as a state inwhich the value of the shift register 1 equals that long code number,and the value of the shift register 2 is set at “all 1's”. Thus, therange of the long code number is from 00000000000h through IFFFFFFFFFFh.The MSB of the long code number is first input to the leftmost bit ofthe shift register 1 of the generator of FIG. 19.

[0409] The reverse long code has a period of 2¹⁶ radio frame intervals(that is, 2¹⁰ super frame intervals). Accordingly, the output of thelong code generator is truncated at 2¹⁶ radio frame intervals so that itrepeats the pattern from phase 0 to the phase corresponding to 2¹⁶ radioframe intervals. Thus, the range of the phase varies as shown in Table17 in accordance with the chip rate. In addition, as will be describedlater in 4.1.5.3., the phase of the inphase component of the long codeis shifted from that of the quadrature component by an amount of“shift”.

[0410] Table 17 shows the phases of the two components when the “shift”is set at 1024. The long code generator can implement a state in whichits phase is shifted from the initial state by an amount of any integermultiple of the clock period. TABLE 17 Correspondence between chip rateand ranges of the phase of a reverse link long code. Chip rates Rangesof the phase (chips) (Mcps) In phase component Quadrature 1.024 0through 2¹⁶ × 10240 − 1 1024 through 2¹⁶ × 10240 + 1023 4.096 0 through2¹⁶ × 40960 − 1 1024 through 2¹⁶ × 40960 + 1023 8.192 0 through 2¹⁶ ×81920 − 1 1024 through 2¹⁶ × 81920 + 1023 16.384 0 through 2¹⁶ × 163840− 1 1024 through 2¹⁶ × 163840 + 1023

[0411] 4.1.4.1.3. Short Code

[0412] 4.1.4.1.3.1. Short Code for Symbols other than the Long Code MaskSymbols.

[0413] The following layered orthogonal code sequences are used for thesymbols of all the physical channels except for the perch channels, andfor the symbols other than the long code mask symbols of the perchchannels. A short code consisting of the layered orthogonal codesequences is designated by a code class number (Class) and a code number(Number). The period of the short code varies for each short code classnumber.

[0414]FIG. 20 illustrates a generating method of the short codes whichare each represented as C_(Class) (Number). The period of the shortcodes equals the period of a symbol. Therefore, if the chip rate (spreadspectrum bandwidth) is the same, the short code period varies inaccordance with the symbol rate, and the number of usable short codesalso varies in accordance with the symbol rate. The relationships of thesymbol rate with the short code class, short code period and short codenumber are shown in Table 18.

[0415] The short code numbering system is composed of the code class andcode number, which are represented by 4 bits and 12 bits in the binarynotation, respectively. The short code phase is synchronized with themodulation and demodulation symbols. In other words, the first chip ofeach symbol corresponds to the short code phase=0. TABLE 18 Symbol rate(ksps) Chip rate = Short Number 1.024 4.096 8.192 16.384 Short code ofshort Mcps Mcps Mcps Mcps code class period codes 256 1024 2 4 4 128 5121024 3 8 8  64 256 512 1024 4 16 16  32 128 256 512 5 32 32  16 64 128256 6 64 64 — 32 64 128 7 128 128 — 16 32 64 8 256 256 — — 16 32 9 512512 — — — 16 10 1024 1024

[0416] 4.1.4.1.3.2. Short Codes for Long Code Mask Symbols.

[0417] Apart from the other symbols, the long code mask symbols of theperch channels use as their short codes the orthogonal Gold codes usingM sequences which are obtained from the following generator polynomials.

[0418] (Shift register 1) X⁸+X⁴+X³+X²+1

[0419] (Shift register 2) X⁸+X⁶+X⁵+X³+1

[0420]FIG. 21 shows a configuration of a short code generator for thelong code mask symbols. The initial value of the shift register 1 is ashort code number N_(LMS) (value range: 0-255) for the long code masksymbol. The MSB of the number N_(LMS) is first input in the leftmost bitof the shift register 1. The initial value of the shift register 2 is“all 1's”.

[0421] If “all 1's” of the shift register 2 is detected, the shiftoperation is halted and “0” is inserted. The first chip of the shortcode output becomes 0. The period of the short code is one symbolinterval (256 chips) of the perch channel.

[0422] 4.1.4.2. Allocation Method of Spreading Codes.

[0423] 4.1.4.2.1. Forward Long Code.

[0424] In the system operation, all the sectors in a cell share a commonsingle long code number allocated thereto. In the system configuration,different long code numbers can be allocated to respective sectors. Thelong code number is designated. With respect to the forward long codesused in the various forward physical channels which are transmitted inthe sector, the same long code number is used by the entire physicalchannels. Concerning the long code phase, see 4.1.3.

[0425] 4.1.4.2.2. Reverse Long Code.

[0426] A long code number is allocated to each reverse link physicalchannel. designated. The long code number is dedicated physical channelsinto which the TCH, ACCH and UPCH are mapped use the reverse link longcode allocated to each mobile station. Dedicated physical channels, intowhich the other logical channels are mapped, and a common physicalchannel use the reverse link long code allocated to each base station.About the long code phases, see 4.1.3.

[0427] 4.1.4.2.3. Short Codes

[0428] 4.1.4.2.3.1. Short Codes for Physical Channels other than thePerch Channels.

[0429] These short codes are allocated to each forward/reverse linkphysical channel. The short code numbers are designated. In terms of thesystem configuration, the same short code number is simultaneouslyusable in the same sector.

[0430] 4.1.4.2.3.2. A Short Code for the Perch Channel.

[0431] A short code number for symbols on the first perch channel otherthan the long code mask symbols is common to all the cells, which isC₈(0). (However, any short code designated is usable for the first perchchannel). A short code number for the long code mask symbols of thefirst perch channel is common to all the cells, which is N_(LMS)−1.(However, any short code number NLMS designated for the long code masksymbol is usable for the long code mask symbol of the first perchchannel).

[0432] As a short code number for long code mask symbol of the secondperch channel, one of the short codes that are assigned to the system inadvance is used for each sector. The short code numbers of these shortcodes are stored in the BSC (base station control center) and mobilestations. (However, any short code for the long code mask symboldesignated is usable for the second perch channel). The short codenumber for the long code mask symbol of the second perch channel has oneto many correspondence with the forward long codes used in the samesector.

[0433] Examples of the correspondence are shown in Table 19. Thecorrespondence is stored in the BSC and mobile stations. (However, anyshort code for the long code mask symbol and any forward long codeswhich are designated for the second perch channel are usable in the samesector). TABLE 19 Examples of the correspondence of the short codes forthe second perch channel with the forward link long codes. Short codenumbers N_(TPC) for long code mask symbols on the second perch channelForward long codes 2 00001h through 00020h 3 00021h through 00040h 400041h through 00060h 5 00061h through 00080h

[0434] 4.1.5. A Generating Method of a Spread Spectrum ModulationSignal.

[0435] 4.1.5.1. Spread Spectrum Modulation Scheme.

[0436] Forward/reverse link: QPSK (BPSK is applicable, as well).

[0437] 4.1.5.2. Allocation Method of Short Codes.

[0438] In accordance with the designated short code numbering system(code class number; Class; and code number, Number), the same short codeis assigned as the inphase short code SCi and the quadrature short codeSCq. In other words, SCi=SCq=C_(class) (number). Different short codenumbering systems are assigned to the forward and reverse links,respectively. Accordingly, the forward and reverse links can usedifferent short codes.

[0439] 4.1.5.3. An Allocation Method of the Long Codes.

[0440] A long code number LN: Assuming that the output value of the longcode generator is G_(LN)(Clock) at the time when the shift registers 1and 2 of the long code generator are shifted by the clock shift numberClock from the initial value 0 (in which the long code number is set inthe shift register 1, and all 1's are set in the shift register 2), theinphase output value LCi(PH) and the quadrature output value LCq(PH) ofthe long code generator at the long code phase PH shown in FIGS. 85-88are as follows for both the forward and reverse links.

LCi(PH)=G_(LN)(PH)

LCq(PH)=G_(LN)(PH+Shift) (=0, in BPSK)

[0441] About the ranges of the inphase and quadrature long code phases,see 4.1.4.1.

[0442] 4.1.5.4. A Generating Method of a Long Code+Short Code.

[0443]FIG. 22 illustrates a generating method of an inphase spreadingcode Ci and a quadrature spreading code Cq using a long code and shortcode.

[0444] 4.1.5.5. A Configuration of a Spreader.

[0445]FIG. 23 shows a configuration of a spreader for generating theinphase component Si and quadrature component Sq of a spread signal byspreading the inphase component Di and quadrature component Dq of thetransmitted data with the spreading codes Ci and Cq.

[0446] 4.1.6. Random Access Control.

[0447]FIG. 24 illustrates a random access transmission scheme. A mobilestation transmits a RACH at a timing which are randomly delayed from thereceived frame timing of the forward common control channel. The randomdelay amount is one of the 16 offset timings as shown in FIGS. 85-88.The mobile station randomly selects one of the offset timings each timeit sends the RACH. One radio frame is transmitted for each transmissionof the RACH. Detecting the RACH with which the CRC result for eachinternal encoding unit is correct, the base station transmits, using theACK mode of the FACH-S, the PID of that RACH in the FACH radio framefollowing the FACH radio frame that is being transmitted at thedetection timing of the RACH. The mobile station transmits, afterreceiving the ACK for the current radio frame over the ACK mode FACH-S,the next radio frame, in the case where multiple RACH radio frames to betransmitted are present.

[0448] The mobile station uses, when one piece of CPS information to betransmitted consists of a plurality of RACH radio units, the same PIDvalue for all these RACH radio units. In addition, it uses one of theRACH-L and RACH-S, inhibiting mixed use of them for the transmission ofthe one piece of the CPS information. The mobile station retransmits theRACH in a case where it cannot receive over the ACK mode FACH-S the PIDvalue of the RACH it transmitted even if TRA msec has passed after thetransmission of the RACH. In this case, it uses the same PID value. Themaximum number of retransmissions is NRA (Thus, the same RACH radio unitcan be transmitted NRA+1 times at the maximum including the firsttransmission). The ACK mode of the FACH-S can contain up to seven PIDsof the RACHs with which the detection result of the CRC is correct.

[0449] If any RACH is present with which the base station detects thatthe CRC is correct and to which it has not yet sent back the ACK by thetime immediately before the transmission of the FACH radio frame, thebase station transmits the ACK mode FACH-S over the first FACH in theorder of received timings of the RACHs with which the CRC is correct.However, those RACHs with which TACK msec has elapsed after detectingthe correct CRC are excluded from those to be transmitted over the ACKmode FACH-S.

[0450] 4.1.7. Multicode Transmission.

[0451] The multicode transmission is carried out as follows when adesignated single RL-ID consists of a plurality of dedicated physicalchannels (spreading codes), so that the pilot coherent detection andtransmission power control are carried out in common to all thededicated physical channels in the single RL-ID. When a plurality ofRL-IDs are assigned to a single mobile station, the pilot coherentdetection and transmission power control are carried out for each RL-ID.

[0452] The frame timings and long code phases are aligned in all thephysical. channels in the single RL-ID. One or both of the following twotransmission methods of the pilot symbols and TPC symbols are used so asto improve the coherent detection characteristics and to reduce theerror rate of the TPC symbols.

EXAMPLE 1 (see, FIG. 25)

[0453] The pilot symbols and TPC symbol are transmitted through one ofthe plurality of dedicated physical channels in the single RL-ID. Thepilot symbols and TPC symbol are not transmitted through the otherdedicated physical channels. The pilot symbols and TPC symbol aretransmitted through that one dedicated physical channel at thetransmission power a few times greater than the transmission power atwhich symbols other than the pilot symbols and TPC symbol aretransmitted through the dedicated physical channels in the RL-ID.

[0454] The amplitude ratio of the transmission power of the pilotsymbols and TPC symbol (pilot portion) to that of the data symbolsection (data portion) has an optimum value in terms of capacity thatminimizes Eb/Io. This is because there is a tradeoff between the factthat the channel estimation accuracy is degraded when the amplitude ofthe pilot portion is reduced, and the fact that the overhead isincreased when the amplitude of the pilot portion is increased.

[0455]FIG. 26 illustrates a simulation result of the optimum valueestimation of the amplitude ratio of the two transmission powers. InFIG. 26, the horizontal axis represents the ratio of the amplitude (AP)of the transmitted wave of the pilot portion to the amplitude (AD) ofthe transmitted wave of the data portion, which are designated in FIG.25 by AP and AD, respectively (in FIG. 25, they are represented as thesquares Ap² and AD² of the amplitudes because the vertical axis of FIG.25 represents the transmission power).

[0456] The vertical axis of FIG. 26 represents the required Eb/Io as inFIGS. 5 and 6. The required quality is BER=10⁻³, and the multicodenumber is three. The simulation result in FIG. 26 shows that the optimumvalue in terms of capacity is obtained when the amplitude AP is twicethe amplitude AD. Considering this from the viewpoint of thetransmission power ratio, the total transmission power of the dataportions of all the physical channels becomes 3AD² in the case of thethree multicode transmission, and the transmission power of the pilotportion becomes Ap²=(2AD)²=4AD². Thus, the optimum transmission powerratio is obtained when the transmission power of the pilot portion is4/3 times that of the data portion.

[0457] As described above, there is an optimum value of the transmissionpower ratio between the pilot portion and the data portion, and theoptimum value varies depending on the number of the multicodes.Accordingly, the transmission power ratio between the pilot portion andthe data portion is made variable. The dedicated physical channel fortransmitting the pilot symbols and TPC symbol are designated.

EXAMPLE 2 (see, FIG. 27).

[0458] In all the dedicated physical channels in the single RL-ID, onlythe pilot symbol and TPC symbol section uses a short code a particulardedicated physical channel uses. The particular dedicated physicalchannel is designated. The pilot portions are added in the same phasewhen they are spread by the same short code, achieving the same effectas when the transmission is carried out with increased transmissionpower.

[0459] 4.1.8. Transmission Power Control.

[0460] FIGS. 89-94 show transmission patterns of the respective physicalchannels.

[0461] 4.1.8.1. Perch Channels.

[0462] The first perch channel is transmitted continuously at designatedtransmission power PP1 except for the long code mask symbol contained ineach time slot. Through the first perch channel, the long code masksymbol contained in each time slot is transmitted at the transmissionpower lower than PP1 by a designated value Pdown.

[0463] The first perch channel is always transmitted in theabove-mentioned method regardless of the presence or absence of thetransmission information of the BCCH1 and BCCH2 which are mapped intothe first perch channel. If the transmission information is not present,an idle pattern (PN pattern) is transmitted. Through the second perchchannel, only the long codemask symbol contained in each time slot istransmitted without transmitting the other symbols. The long code masksymbol of the second perch channel is transmitted at the same time asthe long code mask symbol of the first perch channel. The transmissionpower is a designated value PP2, which is invariable. The values PP1,Pdown and PP2 are determined such that mobile stations located incontiguous sectors can make a sector identification.

[0464] 4.1.8.2. Forward Common Control Physical Channels (FACHs).

[0465] In a radio frame of both the FACH-L and FACH-S, in which notransmission information is present, the transmission is made OFF overthe entire period of the radio frame including the pilot symbols.

[0466] A radio frame of the FACH-L, which contains transmissioninformation, is transmitted at a designated transmission power value PFLover the entire period of the radio frame. The transmission power levelcan be designated for each transmission information, which means thatthe transmission power level is variable from radio frame to radioframe, although it is fixed at the transmission power value PFL withineach radio frame.

[0467] If one or more of the four FACH-S'es in a radio frame beartransmission information, only the time slots of the FACH-S'es includingthe transmission information are transmitted at a designatedtransmission power level. The transmission power value is designated foreach transmission information in “Normal mode” FACHs, which means thattransmission power levels PFS1-PFS4 are variable from FACH-S to FACH-Sin the radio frame. If all of the four FACH-S'es in a radio frame beartransmission information, the radio frame is transmitted over its entireperiod. The transmission power, however, is variable for each FACH-S.

[0468] The transmission power of the “Ack mode” FACH-S is fixed at adesignated transmission power PACK. In the time slots of the FACH-L orFACH-S that bears transmission information, those at both sides of asymbol section for a logical channel are designed such that theytransmit pilot symbols without exception. Accordingly, if a time slot ofa FACH that bears transmission information is followed by a time slot ofa FACH that does not bear any transmission information, the latter timeslot must send pilot symbols that are adjacent to the former time slot.The transmission power level of the pilot symbols is made equal to thatof the former time slot.

[0469] If two time slots of FACHs that bear transmission information areadjacent, the transmission power of the pilot symbols in the second timeslot (that is, the pilot symbols adjacent to the first time slot) isplaced at the level equal to the higher transmission power of the twotime slots. The values PFL, PFS1-PFS4 are determined in accordance withthe received SIR of the perch channel in a mobile station, which isincluded in the RACH.

[0470] 4.1.8.3. Forward Common Control Physical Channel (for PCH)

[0471] The two PD portions included in each group are always transmittedin all the groups. The transmission power is designated at atransmission power level PPCH. When transmitting the PD portion, pilotsymbols are transmitted together with the PD portion of the time slotinto which the PD portion is mapped, although the pilot symbols in thesubsequent time slot are not transmitted. The I portion of each group isdivided into four time slots (I1-I4), and only I portion of a group thatcontains incoming call information is transmitted. The I portions of theremaining groups without any incoming call information are nottransmitted. The transmission power is designated at a transmissionpower level PPCH.

[0472] The time slot, into which the I portion of the group includingthe incoming call information is mapped, is handled such that the pilotsymbols are transmitted at both sides of the symbols for the logicalchannel without exception. Accordingly, if a time slot associated withthe I portion of a group including incoming call information is followedby a time slot associated with the I portion of a group that does notbear any incoming call information, the latter time slot must send pilotsymbols. The PPCH value is determined such that almost all the mobilestations in the sector can receive.

[0473] 4.1.8.4. Reverse Common Control Physical Channels (RACHs)

[0474] A reverse common control physical channel is transmitted from amobile station only when transmission information takes place. It istransmitted on each radio frame unit basis. The transmission powers PRLand PRS of the RACH-L and RACH-S are determined by the mobile station inan open-loop system, and are fixed within a radio frame. To the finalposition of the radio frame, pilot symbols are added to be transmitted.The transmission power of the pilot symbols is the same as that of thepreceding radio frame.

[0475] 4.1.8.5. Forward Dedicated Physical Channel.

[0476] The transmission power control of the forward dedicated physicalchannel is carried out, regardless of the originating or terminatingcall connection or of the diversity handover, such that the transmissionis started at a designated transmission power value PD during theinitial set of the forward dedicated physical channel, and thetransmission power is incremented at fixed intervals until thecommunication power level reaches a value PD. After that, thetransmission power is further incremented at fixed intervals until thereceiving synchronization of the reverse dedicated physical channel isestablished (see 5.2.1.2.2., for details) .

[0477] Until the receiving synchronization of the reverse dedicatedphysical channel has been established, and the decoding of the reverseTPC symbols becomes possible, the transmission is carried outcontinuously at the fixed transmission power PD. The value PD isdetermined in the same method as that of the FACH.

[0478] When the receiving synchronization of the reverse dedicatedphysical channel has been established, and the decoding of the reverseTPC symbol becomes possible, high speed closed loop transmission powercontrol is started in accordance with the decoded result of the TPCsymbols. In the high speed closed loop transmission power control, thetransmission power is controlled at a control step of 1 dB at every timeslot interval in accordance with the decoded result of the TPC symbols.For details of the transmission power control method of the forwarddedicated physical channel, see 5.2.1.1.

[0479] 4.1.8.6. Reverse Dedicated Physical Channels.

[0480] In an originating or terminating call connection, a mobilestation starts transmission of a reverse dedicated physical channel,after a receiving synchronization establishing process of the forwarddedicated physical channel meets predetermined conditions. Thetransmission power level of the first time slot at the beginning of thetransmission is determined in the open loop system as in the RACH, andthe subsequent transmission power level of the time slots is determinedby the high speed closed loop transmission power control in accordancewith the decoded result of the TPC symbols in the forward dedicatedphysical channel. For more detailed information, see 5.2.1.1.

[0481] In the diversity handoff, it is not necessary to establish anynew reverse dedicated physical channel. The transmission power iscontrolled from time slot to time slot by the high speed closed looptransmission power control during the diversity handover. For moredetailed information about the transmission power control method of thereverse dedicated physical channel, see 5.2.1.1.

[0482] 4.1.9. DTX (Data Transmission Equipment) Control.

[0483] The DTX control is applied only to the dedicated physicalchannels.

[0484] 4.1.9.1. Dedicated Physical Channels for DTCH and ACCH.

[0485] 4.1.9.1.1. Transmission.

[0486] Only in the dedicated physical channels (32 ksps) for voiceservice, the transmission of symbols for a DTCH is made ON when voiceinformation is present, and made OFF when no voice information ispresent. Examples of the transmission patterns are shown in FIG. 94.

[0487] The pilot symbols and TPC symbol are always transmittedregardless of the presence and absence of the voice information andcontrol information. The power ratio of the transmission power (Pon)while the transmission is ON to the transmission power (Poff) while thetransmission is OFF meets the transmission ON/OFF ratio of thetransmission characteristics of 5.1.1.

[0488] The transmission ON/OFF patterns are identical in all the 16 timeslots in a radio frame. The DTX control is carried out on a radio frame(10 msec) basis. The DTX is not carried out in the dedicated physicalchannels (equal to or greater than 64 ksps) for data transmission. Theyare always in a transmission ON state. The information for notifying ofthe presence and absence of the voice information and controlinformation is not transmitted.

[0489] 4.1.9.1.2. Reception.

[0490] Table 20 shows methods of making decisions as to whether or notthe voice information and the control information are present. TABLE 20Methods of deciding the presence and absence of voice information andcontrol information Information type Information is present Informationis absent Voice CRC on a DTCH selection CRC on a DTCH selectioninformation combining unit basis is combining unit basis is correct; ora power ratio of incorrect; and a power ratio the average received powerof the average received of the pilot and TPC power of the pilot and TPCsymbols to the average symbols to the average received power of thereceived power of the DTCH symbols is equal to DTCH symbols is equal toor more than P_(DTX) dB. or less than P_(DTX) dB. Control CRC on an ACCHCRC on an selection information selection combining unit combining basisis basis is correct. incorrect.

[0491] The average received power of the symbols in Table 20 is theaverage value of the received power of all the associated symbols in theradio frame. The value P_(DTX) (dB) is one of the system parameters.

[0492] 4.1.9.2. Dedicated Physical Channels for SDCCHs.

[0493] The transmission of symbols for the SDCCH is made ON when controlinformation to be transmitted is present, and made OFF when no controlinformation is present. The pilot symbols and TPC symbol are alwaystransmitted regardless of the presence and absence of the controlinformation. The power ratio of the transmission power (Pon) while thetransmission is ON to the transmission power (Poff) while thetransmission is OFF meets the transmission ON/OFF ratio of thetransmission characteristics defined in 5.1.1. The transmission ON/OFFpatterns are identical in all the 16 time slots in a radio frame.

[0494] The DTX control is carried out on a radio frame (10 msec) basis.A receiving side carries out the processing in accordance with theCPS-PDU assembling method as illustrated in FIGS. 95A and 95B. It is notnecessary to make a decision as to whether the control information ispresent or not.

[0495] 4.1.9.3. Dedicated Physical Channels for UPCHs.

[0496] The transmission of symbols for a UPCH is made ON when controlinformation or user information to be transmitted is present, and madeOFF when neither of them is present. The BTS has three modes about thepilot symbols and TPC symbol.

[0497] Mode 1.

[0498] The modes are designated. The need for transmission is decidedfor each radio frame. The transmission of the entire pilot symbols andTPC symbol in a radio frame is halted if both the following conditions 1and 2 are satisfied. The transmission of the entire pilot symbols andTPC symbol in the radio frame is restarted if the following condition 3or 4 is detected.

[0499] Condition 1: FNDATA or more radio frames have passed after thecontrol information or user information to be transmitted is completed.

[0500] Condition 2: Incorrect CRC results of received radio frames arecontinuously detected for FCRC or more radio frames.

[0501] Condition 3: Control information or user information to betransmitted takes place.

[0502] Condition 4: A correct CRC result of a received radio frame isdetected.

[0503] A mobile station decides the transmission ON/OFF of the pilotsymbols and TPC symbol using the presence and absence of the controlinformation or user information to be transmitted in connection with thedetection result of an out-of-sync. When the control information or userinformation to be transmitted takes place after halting the transmissionof the pilot symbols and TPC symbol, radio frames into which an idlepattern is inserted in advance are sent by FIDL frames, followed by thetransmission of a radio frame into which the control information or userinformation to transmitted is inserted. In this case, the pilot symbolsand TPC symbol are also transmitted in the radio frames into which theidle pattern is inserted.

[0504] Mode 2.

[0505] In a radio frame without the control information or userinformation, the pilot symbols and TPC symbol are transmitted in part ofthe slots. One or more slots, which transmit the pilot symbols and TPCsymbol in the radio frame without the control information or userinformation, are designated by a parameter P_(freq) indicating theocurrence frequency of transmission. Table 21 shows the relationshipsbetween the parameter P_(freq) and the slots that transmit the pilotsymbols and TPC symbol. TABLE 21 Relationships between P_(freq) andslots that transmit pilot symbols and TPC symbol. P_(freq) Slot Nos.that transmit pilot and TPC symbols 0 All slots (slot Nos. 1 through 16)1 1, 3, 5, 7, 9, 11, 13 and 15 2 1, 5, 9 and 13 3 1 and 9 4 1 5 Nosymbols are sent

[0506] The high speed closed loop transmission power control followsonly the TPC symbols from the mobile station which are determined inaccordance with the pilot symbols and TPC symbols the BTS transmits, andignores the TPC symbols from the mobile station which are determined inaccordance with the pilot symbols and TPC symbols the BTS does nottransmit. Therefore, the transmission power control intervals varydepending on the Pfreq values.

[0507] Mode 3

[0508] The pilot symbols and TPC symbol are always transmittedregardless of the presence and absence of the control information anduser information. With regard to the pilot symbols and TPC symbol in theUPCH symbols and in the mode 1, the power ratio of the transmissionpower (Pon) while the transmission is ON to the transmission power(Poff) while the transmission is OFF meets the transmission ON/OFF ratioof the transmission characteristics defined in 5.1.1. The transmissionON/OFF patterns are identical in all the 16 time slots in a radio frame.

[0509] The DTX control is carried out on a radio frame (10 msec) basis.A receiving side always carries out the processing in accordance withthe CPS-PDU assembling method as illustrated in FIGS. 96A and 96B. It isnot necessary to make a decision as to whether the control informationor user information is present or not

[0510] 4.1.10. A Bit Transmission Method.

[0511] CRC bits are sent from the higher to lower order bits. The TCH istransmitted in the input order. The tail bits transmitted are all “0's”.Dummy bits consist of “1's”. The dummy bits are included in the CRCencoding. An idle pattern is inserted into the entire CRC.

[0512] Encoded fields (shadowed portions in FIGS. 64A, 64B, 84A and 84B)on a selection combining unit or internal encoding unit basis. Thesefields include the CRC checking bits, as well. The idle pattern consistsof any PN pattern, and the same pattern is used in common to all theinternal encoding units or selection combining units of each logicalchannel. In addition, the idle pattern is arranged such that it causesan incorrect CRC result when no error takes place in the received side.

[0513] 4.1.11. Paging Control.

[0514] 4.1.11.1. The Operation of a Base Station (BTS).

[0515] Mobile stations are divided into groups in a predeterminedmanner, and are subject to paging on a group by group basis. The BTScarries out the grouping, and designates the corresponding group numberusing the paging information containing the identification number of acalled mobile station.

[0516] The BTS transmits the paging information using the I portions(I1-I4) of the PCH of the designated group number. The BTS places “all0's” in the two PD portions (PD1 and PD2) in the PCHs of the groupshaving no paging information, and transmits them without transmittingthe I portion. Being designated to transmit the paging information, theBTS places “all 1's” in the PD1 and PD2 of the PCH associated with thedesignated group number, and transmits the designated paging informationusing the I portion of the same PCH.

[0517] 4.1.11.2. The Operation of a Mobile Station.

[0518] A mobile station usually receives only the 8-bit PD1. It carriesout coherent detection using the pilot symbols (four symbols)immediately previous to the PD1. The mobile station carries out amajority decision processing (soft decision). It is assumed that a valuecomputed by the processing takes “0” when the PD portion is all 0's in astate without degradation in the receiving quality, and takes a positivemaximum value when it is all 1's. The following operations are performedin accordance with the processing result and decided threshold values(M1 and M2, where M1>M2).

[0519] (I) If the processing result is equal to or greater than thedecision threshold the mobile station makes a decision that paging takesplace to any one of the mobile stations of its own group, and receivesthe I portion of the same PCH.

[0520] (2) If the processing result is less than the decision thresholdM2, the mobile station makes a decision that no paging takes place toits own group, and makes the reception OFF until the receiving timing ofthe PD1 of its own group one super frame later.

[0521] (3) If the processing result is equal to or greater than M2 andless than M1, the mobile station receives the PD2 in the same PCH, andcarries out the foregoing (1) and (2). If the processing result of thePD2 is also equal to or greater than M2 and less than M1, the mobilestation receives the I portion of the same PCH.

[0522] (4) Receiving the I portion in the foregoing processing (2) or(3), the mobile station makes a decision from the paging informationcontained in the I portion as to whether the paging to itself takesplace or not.

[0523] 4.2. Transmission Path Interface.

[0524] 4.2.1. Major Characteristics.

[0525] 4.2.1.1. 1.5 Mbps.

[0526]FIGS. 28A and 28B illustrate the mapping into an ATM cell.

[0527] 4.2.1.2. 6.3 Mbps.

[0528]FIGS. 29A and 29B illustrate the mapping into an ATM cell, andFIG. 30 shows a pulse mask.

[0529] 4.2.2. Protocol.

[0530] 4.2.2.1. ATM Layer.

[0531] Codings of the VPI (virtual path identifier), VCI (virtualchannel identifier) and CID (channel identifier) in the ATM layer in theinterface between the base station (BS) and the switching center willnow be described.

[0532]FIG. 31 shows the link structure between the BTS and MCC.

[0533] (1) Interface Specifications.

[0534] Channel numbers: Channel numbers are assigned to individual HWYsbetween the base station and the switching center. The correspondencebetween the physical HWY interface mounted positions and the channelnumbers are fixedly set in advance. The range of the channel numbers is0-3 for the 1.5M-HWY, and only 0 for 6.3M-HWY.

[0535] VPI: The VPI value is only “0”, and the VPI is not usedsubstantially.

[0536] VCI: 256/VPI

[0537] CID: 256/VPI. 256/VCI.

[0538] (2) ATM Connection.

[0539] VCI=64: Used for timing cell. A minimum channel number for eachBTS is used. The following VCIs can be set as the VCIs other than thoseused for super frame phase correction. In connection with this, the AALtypes used in the respective VCIs are also shown.

[0540] VCIs for control signals between BTS and MCC: AAL-Type 5.

[0541] VCls for paging: AAL-Type 5.

[0542] VCls for transmitted signals between MS and MCC: AAL-Type 2.

[0543] When a plurality of channel numbers are set in the BTS, the VCIsother than those used for the super frame phase correction areassignable to any channel numbers by any number. The correspondence isestablished between the VCIs other than those used for the super framephase correction, and the channel numbers and VCI values.

[0544] (3) Short Cell Connection.

[0545] A method of using the CID value is set.

[0546] (4) AAL-Type Designation Method.

[0547] The AAL-Type is designated at the time when a wire channel isestablished. Table 22 shows an example of the correspondence between theused transmission information types and the AAL-Types, although thecorrespondence between them can be set freely. TABLE 22 Example ofcorrespondence between wire channel transmission information types andAAL-Types. Transmission information types AAL-Type VCI types DTCHtransmission information 2 For transmission signals ACCH transmissioninformation 2 between MS and MCC SDCCH transmission 2 information BCCH1,2 transmission 5 For control signals information between BTS and MCC PCHtransmission information 5 For paging FACH transmission information 2For transmission signals (for packet transmission) between MS and MCCRACH transmission information (for packet transmission) UPCHtransmission information Control signals between BTS 5 For controlsignals and MCC VCI types between BTS and MCC

[0548] (5) Idle Cells.

[0549]FIG. 32 shows an idle cell on an ATM channel. An idle cellaccording to ITU-T standard is used.

[0550] 4.2.2.2. AAL-Type 2

[0551] AAL-Type 2 is a protocol of an ATM adaptation layer of acomposite cell (AAL type 2) which is transmitted over an interface(Super A interface) section between the base station and switchingcenter.

[0552] (1) AAL-Type 2 Processor.

[0553]FIGS. 33A and 33B show connecting configuration of AAL-Type 2.

[0554] (2)Band Assurance Control.

[0555] In the Super-A section, control for assuring a minimum bandwidthfor each quality class is needed to meet the quality of serviceparameters such as a delay and a cell loss ratio. In AAL-Type 2, theband assurance is carried out which is assigned to each quality class ata short cell level. The short cell quality class falls into thefollowing four classes depending on (a maximum allowable delay time; anda maximum cell loss ratio).

[0556] Quality class 1 (5 ms; 10⁻⁴)

[0557] Quality class 2 (5 ms; 10⁻⁷)

[0558] Quality class 3 (50 ms; 10⁻⁴)

[0559] Quality class 4 (50 ms; 10⁻⁷)

[0560] The quality class which corresponds to the service offered isdesignated when a wire channel is established. The transmission order ofshort cells are determined in accordance with the quality classes, andthe required bandwidth is ensured for each quality class. A concretemethod for ensuring the bandwidth will be described in 5.3.5.

[0561] When one unit of transmission information is longer than themaximum length of the short cell, the transmission information isdivided into a plurality of short cells to be transmitted. In this case,the plurality of short cells are transmitted continuously using the sameVCI. The continuity is ensured only within the same VCI, but not ensuredbetween different VCIs. In other words, a standard cell with another VCIcan intervene between the short cells to be transmitted.

[0562] 4.2.2.3. AAL-Type 5

[0563] AAL-Type 5 as well as AAL-Type 2 is used as the AAL of ATM cellstransmitted on the Super A interface between the base station andswitching center. In AAL-Type 5, the SSCOP (Service Specific ConnectionOriented Protocol) is supported between the base station and switchingcenter.

[0564] (1) AAL-Type 5 Processor.

[0565]FIGS. 34A and 34B show connecting configuration of AAL-Type 2.

[0566] (2) Band Assurance Control.

[0567] In the Super-A section, control for assuring a minimum bandwidthfor each quality class is needed to meet the quality of serviceparameters such as a delay and a cell loss ratio. The quality classesare shown below. In AAL-Type 5, the band assurance is carried out whichis assigned,to each quality class at a VCI level. The quality classfalls into the following five classes in accordance with (a maximumallowable delay time; and a maximum cell loss ratio).

[0568] Interrupt (0; 0) Highest priority cell.

[0569] Quality class 1 (5 ms; 10⁻⁴)

[0570] Quality class 2 (5 ms; 10⁻⁷)

[0571] Quality class 3 (50 ms; 10⁻⁴)

[0572] Quality class 4 (50 ms; 10⁻⁷)

[0573] The quality class which corresponds to the service offered isdesignated when a wire channel is established. The transmission order ofstandard cells are determined in accordance with the quality classes,and the required bandwidth is ensured for each quality class. A concretemethod for ensuring the bandwidth will be described in 5.3.5. Theinterrupt ,buffer cell is given the highest priority (with a minimumdelay, inhibiting discarding) to be output.

[0574] 4.2.3. Signal Format:

[0575] 4.2.3.1. The Format of AAL-2.

[0576]FIG. 35 illustrates the format of AAL-2.

[0577] A start field (one octet). OSF: Offset field. SN: Sequencenumber. P: Parity.

[0578] SC-H (Short cell header: three octets). CID: Channel identifier:O/PADDING; 1/ANP; 2-7/RESERVED.

[0579] LI: Payload length.

[0580] PTT: CPS-Packet Payload Type: It includes start/continue and endinformation of the payload.

[0581] UUI: CPS-User to User indication.

[0582] When one unit of transmission information is divided in aplurality of short cells to be transmitted, the, UUI and the pluralityof short cells bearing the divided transmission information to betransmitted are continuously transmitted using the same VCI, for thereceiving side to be able to assemble the transmission information.

[0583] 000/single short cell.

[0584] 001/top and continued.

[0585] 010/continued and end.

[0586] 011/continued and continued.

[0587] HEC: Header Error Check (generator polynomial=x⁵+x²+1).

[0588] SAL (two or three octets).

[0589]FIG. 36 shows the format of the SAL.

[0590] Table 23 shows a specifying method of SAL fields.

[0591] Table 24 shows the presence and absence of the uses of the SALthird octet.

[0592] Table 25 shows a specifying conditions of the SAL fields. TABLE23 Field Uses Set values SAT (SAL SAL field type 00: Wire forward syncstate is OK type) SAT = 1x: Loop Back cell (LB). 01: Wire forward syncstate is NG SAT = 0x: Other than that 10: Return indication (forward)mentioned above 11: Return indication (reverse) FN (frame DHO framealignment SAT = 00 0-63: Frame number number) Frame number SAT = 011-63: Forward FN sliding number. Sync Radio out-of-sync detection 1:Out-of-sync state. 0: Sync state BER BER degradation detection 1: Detectdegradation 0: Normal Level Level degradation detection 1: Detectdegradation 0: Normal CRC CRC checking result 1: NG. 2: OK SIR ReceivedSIR 0-15: Received SIR increases with value RCN (radio Radio channelnumber 0-15: Radio channel sequence channel number number) RSCN (radioRadio subchannel number 0-15: Radio subchannel sequence subchannelnumber number

[0593] TABLE 24 The used state of the SAL third octet. During singlecode During multicode communications communications Remarks Frame inradio Both RCN (radio Only RCN is used. channel is not channel number)divided. and RSCN (radio subchannel number) are unused. Frame in radioOnly RSCN is used. Both RCN and channel is RSCN are used divided.

[0594] The division of the radio channel frame is carried out when 128kbps or more unrestricted digital service is provided, and 256 ksps ormore dedicated physical channel is used. The unit of division is theunit, on the basis of which the external encoding at a user informationrate of 64 kbps (1B) is carried out. See, FIGS. 78A-80C.

[0595] All “Os” is filled when unused.

[0596] The multicode transmission is applied only to the DTCH and UPCH.Accordingly, RCN is applied only to the DTCH and UPCH. TABLE 25 SALfield specified values DTCH ACCH SDCCH RACH FACH UPCH R F R F R F R F RF SAT*¹ O O O O O O O O O O FN O O O O O All 0 O All 0 O All 0 Sync OAll 0 O All 0 All 0 All 0 All 0 All 0 All 0 All 0 BER O All 0 O All 0 OAll 0 O All 0 O All 0 Level O All 0 O All 0 O All 0 O All 0 O All 0 CRCO All 0 All 0 All 0 All 0 All 0 All 0 All 0 All 0 All 0 SIR O All 1 OAll 1 O All 1 O All 1 O All 1 RNC*² O O Reserved Reserved ReservedReserved Reserved Reserved Reserved Reserved RCSN*² O O ReservedReserved Reserved Reserved Reserved Reserved Reserved Reserved

[0597] 4.2.3.2. Format of AAL-5.

[0598]FIG. 37 shows a format of an AAL-5 cell. To the LAST cell, a PADand CPCS-PDU trailer are added. PAD (CPCS padding). It is used foradjusting the frame length to become 48 octets (all “0s”).

[0599] CPCS-PDU trailer.

[0600] CPCS-UU: CPCS user to user indicator. It is used fortransparently transferring information used in a higher layer.

[0601] CPI: Common part type indicator. Uses are not yet defined. All“0s” are set at the present.

[0602] LENGTH: CPCS-PDU payload length. It indicates a user informationlength in byte.

[0603] CRC: Cyclic redundancy code. It is used for detecting errors ofthe entire CPCS frame. The generatorpolynomial=X³²+X²⁶+X²³+X²²+X¹⁶+X¹²+X¹¹+X¹⁰+X⁸+X⁷+X⁵+X⁴+X²+X+1.

[0604] 4.2.3.3. Timing Cell.

[0605]FIGS. 38A and 38B illustrate a signal format of a timing cell thatis used for a SFN (System Frame Number) synchronization establishingprocessing when starting the BTS. Table 26 shows a method of specifyinginformation elements in the signal format. See 5.3.8 for the SFNsynchronization establishing method of the BTS using the timing cell.TABLE 26 Method of specifying timing cell information elementsInformation elements Specified contents Specified values Channel number 0 VPI  0 VCI VCI for timing cell 64 Message ID 02h: Timing report(MCC→BTS) 03h: Timing report (BTS→MCC) Other values: reserved Correctionnumber All “0s” Correction range All “0s” Transmission delay All “0s” SFtime information Timing cell received time in Table 27 shows the(received, MCC-SIM side) MCC. It indicates the time in a correspondencesuper frame. Resolution is 125 μsec. between bits and times. SF timeinformation Timing cell transmitted time in (transmitted, MCC-SIM MCC.It indicates the time in a side) super frame. Resolution is 125 μsec. SFtime information All “0s” (this information (received, BTS side) elementis not used in the present system). SF time information Timing celltransmitted time in Table 27 shows the (transmitted, BTS side) BTS. Itindicates the time in a correspondence super frame. Resolution is 125μsec. between bits and times. SF phase shift value All “0s” (thisinformation element is not used in the present system). LC counterinformation The position of a super frame in a The value ranges(received, MCC side) long code period when the timing over 0-2¹⁰-1, andis cell is received in the MCC (See, represented in binary FIG. 39).coding. LC counter information The position of a super frame in a(transmitted, MCC side) long code period when the timing cell isreceived from the MCC (See, FIG. 39). LC counter information All “0s”(this information (received, BTS side) element is not used in thepresent system). LC counter information The position of a super frame ina The value ranges (transmitted, BTS side) long code period when thetiming over 0-2¹⁰- 1, and is cell is received in the BTS (See,represented in binary FIG. 39). coding. LC counter shift value All “0s”(this information element is not used in the present system). CRC-10 Thevalue of CRC-10 for ATM cell payload. Generator polynomial: X¹⁰ + X⁹ +X⁵ + X⁴ + X + 1.

[0606] TABLE 27 Correspondence between SF time information bits andtimes Bits Times (msec) 0h 0 1h 0.125 2h 0.250 . . . . . . 13FFh 639.875

[0607] 4.2.4. Clock Generation.

[0608] Generated clocks (examples)

[0609] (1) Radio synthesizer reference clock.

[0610] (2) 4.096 Mcps (chip rate).

[0611] (3) 1/0.625 msec. (radio time slot).

[0612] (4) 1/10 msec. (radio frame).

[0613] (5) 1/640 msec. (radio super frame; phase 0-63).

[0614] (6) 1.544 Mbps, 6.312 Mbps (transmission line clock).

[0615] 5. Functional Configuration.

[0616] 5.1. Radio Stage, and Transmitting and Receiving Amplifier.

[0617] 5.1.1. Pilot Coherent Detection RAKE.

[0618] 5.1.1.1. Pilot Coherent Detection RAKE Configuration.

[0619] (1) RAKE Combiner.

[0620] Allocate fingers so that sufficient receiving characteristics canbe obtained for respective diversity branches (space and inter-sectordiversities). The algorithm for assigning the fingers to the branches isnot specified. The diversity combining method is a maximal ratiocombining.

[0621] (2) Searcher.

[0622] A searcher selects paths for RAKE combining from among receivedbranches to achieve optimum receiving characteristics.

[0623] (3) A Pilot Coherent Detection Channel Estimation Method.

[0624] The coherent detection is carried out using pilot blocks(consisting of four pilot symbols each) which are received at every0.625 ms interval.

[0625] 5.1.1.2. Channel Estimation Using Multi-Pilot Blocks.

[0626] A channel estimation method using multiple pilot blockssandwiching an information symbol section will be described below withreference to FIG. 40.

EXAMPLE

[0627] The following is a description of a channel estimation processingof an information section between time −3Tp<t<−2Tp, which is carried outat time t=0 by averaging three pilot blocks each before and after thatinformation section.

[0628] (a) Carrying out QPSK demodulation of pilot blocks P1-P6.

[0629] (b) Obtaining average values of inphase and quadrature componentsof the four pilot-symbols in each of the pilot blocks P1-P6.

[0630] (c) Multiplying the average values by weighting coefficientsα1-α3, and summing them up.

[0631] (d) Adopting the obtained result as the channel estimate of theinformation symbol section (shadowed) between pilot blocks P3 and P4.

[0632] 5.2. Baseband Signal Processor.

[0633] 5.2.1. Transmission Power Control.

[0634] 5.2.1.1. Outline of the Transmission Power Control.

[0635] (1) RACH transmission power control. The BTS broadcasts over theBCCH the transmission power of the perch channels and the reverseinterfering power. A mobile station decides the transmission power ofthe RACH in accordance with the information.

[0636] (2) FACH transmission power control. The RACH includesinformation about the received SIR of the perch channel, which ismeasured by the mobile station. The BTS decides in accordance with theinformation the transmission power of the FACH associated with the RACHreceived, and designates the transmission power level together with thetransmission information. The transmission power level is variable ateach transmission of the information.

[0637] (3) Forward and reverse transmission power control of thededicated physical channel. Its initial transmission power is decided inthe same manner as the transmission power of the RACH and FACH. Afterthat, the BTS and mobile station proceed to a high speed closed loopcontrol based on the SIR. In the closed loop control, a receiving sideperiodically compares the measured value of the received SIR with areference SIR, and transmits to the transmitting side the comparedresult using the TPC bit. The receiving side carries out relativecontrol of the transmission power in accordance with the TPC bit. Tomeet required receive quality, an outer loop function is provided whichupdates the reference SIR in response to the receive quality. Withrespect to the forward link, range control is carried out which sets theupper and lower limits of the transmission power level.

[0638] (4) Transmission power control during packet transmission. Thetransmission power control of the UPCH is carried out in the same manneras (3) above. That of the RACH during the packet transmission isperformed as (1) above. With regard to the FACH during the packettransmission, the transmission is always carried out at a transmissionlevel specified by the transmission power range designation. Unlike the(2) above, the transmission power level is not varied every time theinformation is transmitted.

[0639] 5.2.1.2. SIR Based High Speed Closed Loop Transmission PowerControl.

[0640] (1) Basic operation. The BTS (or mobile station) measures thereceived SIR every transmission power control interval (0.625 ms), setsthe TPC bit at “0” when the measured value is designated in the reverselink, and the maximum transmission power and minimum transmission powerare designated in the forward link, so that the control is carried outin these ranges (see, FIGS. 41A and 41B). If the TPC cannot be receivedbecause of the out-of-sync, the transmission power level is fixed.

[0641] (2) Forward/reverse frame timings. Frame timings of the forwardand reverse channels are determined such that the positions of the pilotsymbols of the two channels are shifted by ½ time slot, therebyimplementing the transmission power control with one slot control delay(see, FIG. 42).

[0642] (3) Initial operation. FIG. 43 shows a method of shifting fromthe initial state to the closed loop control. First, the forwardtransmission power control will be described first with reference toFIG. 43(A). The BTS carries out transmission in a fixed transmissionpower control pattern until it can receive the TPC bit based on theforward SIR measured result. This is the initial operation. The initialoperation carries out transmission according to a control pattern thatwill increase the transmission power step by step. The initial operationis divided into two stages.

[0643] (a) The BTS, as the first transmission power increasing process,increases the transmission power at every predetermined interval, in thepredetermined number of consecutive times, and by a predeterminedmagnitude. At the end of the first transmission power increasingprocess, the transmission power is set at the designated initialtransmission power level. These values are preset. The purpose of thefirst transmission power increasing process is to avoid a sharp increaseof interfering power to other mobile stations, which will be caused bysudden transmission at large transmission power. The predeterminedvalues are set in such a manner that the transmission power is increasedstep by step so that other mobile stations can follow by thetransmission power control the variations in the interfering powermagnitude. In this case, the TPC bit sequence transmitted over theforward channel is such a fixed pattern (for example, 011011011 . . . )that increases the transmission power of the mobile station stepwise.The pattern is set in advance. If the synchronization of the reversededicated physical channel is established during the first transmissionpower increasing process, the process is halted, and the high speedclosed loop transmission power control is started in accordance with thereceived TPC bit from the mobile station.

[0644] (b) The BTS increases, as the second transmission powerincreasing process, the transmission power at every predeterminedinterval by a predetermined magnitude until the reverse frame alignmentis established. These predetermined values are specified apart fromthose of the foregoing (a). The purpose of the second transmission powerincreasing process is to ensure the establishment of the forward radioframe alignment by increasing step by step the transmission power evenin the case where the initially set transmission power level isinsufficient for the mobile station to establish the forward radio framealignment. The predetermined interval of this process is rather long ofabout one to a few seconds. The pattern of the forward transmissionpower control is variable in accordance with the interfering amount orthe like.

[0645] (c) Establishing the forward frame alignment, the mobile stationstarts the relative control of the transmission power in accordance withthe TPC bits received from the BTS using the transmission powerdetermined in the open loop control as the initial value. In this case,the TPC bits to be transmitted through the reverse channel aredetermined on the basis of the measured values of the forward SIR (see,FIG. 43(B)).

[0646] (d) Establishing the reverse frame alignment, the BTS carries outthe relative, control of the transmission power in accordance with theTPC bits received from the mobile station.

[0647] The BTS can change the fixed TPC pattern mentioned abovedepending on the interfering amount over the entire cell. Although themobile station carries out the foregoing reverse transmission powercontrol in accordance with the fixed TPC bit pattern from the basestation, it can perform similar transmission power control using a fixedcontrol pattern that is preset in the mobile station. In this case, thepattern is invariable.

[0648] Although the initial value of the reverse transmission powerwhich is sent from the mobile station is determined in the open loopcontrol, an initial value sent from the base station can be usedinstead. In this arrangement, because the base station can determine it,a more optimal initial value can be set.

[0649] (4) SIR Measurement Method.

[0650] Requirements for the SIR measurement are: That the transmissionpower control with one slot control delay can be implemented asdescribed above (2). That high SIR measurement accuracy can be achieved.

[0651] Examples of the measurements are shown below.

[0652] (A) Measurement of Received Signal Power (S).

[0653] (a) The measurement of the received signal power S is carried outat every slot interval (transmission power update interval) using pilotsymbols after RAKE combining.

[0654] (b) The received signal power S equals the amplitude square sumof the average values of the absolute values of the inphase andquadrature components of a plurality of symbols.

[0655] (B) Measurement of Interfering Signal Power (I).

[0656] (a) Average signal power is obtained of the pilot symbols andoverhead symbol in a pilot block after the RAKE combining.

[0657] (b) The reference signal point for the individual pilot symbolsis obtained by carrying out the QPSK demodulation (quadrant detection)of the pilot symbols using the root of the foregoing average signalpower.

[0658] (c) The mean square: is obtained of the distances between thereceived points and the reference signal point of the pilot symbols inthe pilot block.

[0659] (d) The interfering signal power is obtained by calculating themoving average of the mean squares over M frames, where M is 1-100, forexample.

[0660] 5.2.1.3. Outer Loop.

[0661] The BTS and MCC have an outer loop function of updating thereference SIR of the high speed closed loop transmission power controlin accordance with quality information to meet the required receivequality (average FER or average BER). The MCC performs during the DHOthe outer loop control in response to the quality after the selectioncombining.

[0662] (1) An update method of the reference SIR. The initial value ofthe reference SIR is designated. The subsequent reference SIR is updatedon the basis of measured results of the receive quality. Both the MCCand BTS can determine the update of the reference SIR. The following isan example of a concrete method.

[0663] i) Designating the start of the quality monitoring.

[0664] ii) Carrying out the designated quality monitoring continuously,and reporting the results of the monitoring.

[0665] iii) According to the quality monitoring results reported, adecision is made whether the update of the reference SIR is to be madeor not. If the update is decided, the reference SIR is set and itsupdate is designated.

[0666] 5.2.1.4. The transmission power control during the inter-sectordiversity handover. During the inter-sector diversity handover, themeasurement of the received SIR and the demodulation of the TPC bits arecarried out with both the forward and reverse links after theinter-sector maximal ratio combining. With regard to the forward TPCbits, the same value is transmitted from a plurality of sectors. Thus,the transmission power control is carried out in the same manner as inthe case where no diversity handover is performed.

[0667] 5.2.1.5. The Transmission Power Control During the Inter-CellDiversity Handover.

[0668] (1) Reverse transmission power control (see, FIG. 44).

[0669] (a) BTS operation. Each BTS measures the reverse received SIR asin the case where no diversity handover is performed, and transmits tothe mobile station the TPC bits determined in accordance with themeasured result.

[0670] (b) Mobile station operation. The mobile station receives the TPCbits from each BTS independently (with carrying out the inter-sectordiversity). At the same time, the mobile station measures thereliability (received SIR) of the TPC bits of each BTS. If anyone of theresults of the soft majority decision about the TPC bits that meet apredetermined reliability includes “0”, the transmission power isreduced by 1 dB. If all the results are “1”, the transmission power isincreased by 1 dB.

[0671] (2) Forward transmission power control (see, FIG. 45).

[0672] (a) BTS operation. Each BTS controls the transmission power inaccordance with the received TPCbits as in the case where no diversityhandover is performed. If the TPC bit cannot be received because of theout-of-sync of the reverse link, the transmission power level is fixed.

[0673] (b) Mobile station operation. The mobile station measures thereceived SIR after the site diversity combining, and transmits to eachBTS the TPC bits which are determined in accordance with the measuredresults.

[0674] 5.2.2. Synchronization Establishing Processing.

[0675] 5.2.2.1. At the Start Up of the Mobile Station.

[0676] (a) Each sector sends the perch channel that masks part of thelong code. At the start up, the mobile station establishes the perchchannel synchronization by carrying out the sector selection using athree step initial synchronization method of the long code.

[0677] (b) Each perch channel broadcasts its own sector number and thelong codes of the peripheral cells. The mobile station establishes onthe basis of the broadcast information the perch channel synchronizationof the remaining sectors in the same cell and of the sectors in theperipheral cells, and measures the received levels of the perchchannels. While the mobile station is standing by, the mobile stationmakes comparison between the received levels of the perch channels ofrespective sectors described above to judge whether the mobile stationhas shifted the sector or not.

[0678] 5.2.2.2. At Random Access Reception.

[0679] The mobile station transmits a RACH when carrying out a locationregistration, or an originating or terminating call. The BTS establishesthe synchronization of the RACH transmitted at a plurality of frameoffsets, and receives it. As shown in FIGS. 85-88B, the RACHsynchronization can be established so that the reception processing ofall the RACH-Ls and RACH-S'es that are transmitted at the four offsettimings per 10 msec. can be completed within 0.625 msec. The receptionprocessing includes deinterleaving, Viterbi decoding and CRC decoding,besides the capability of making a decision as to whether thetransmission of Ack is required or not. The BTS measures the propagationdelay time due to traveling between the mobile station and the BTS,using the delay time of the RACH received timing with respect to apredetermined timing.

[0680] 5.2.2.3. At establishing synchronization of the dedicatedphysical channel (see, FIGS. 87A and 87B). The outline of thesynchronization establishing procedure of the SDCCH and TCH will now bedescribed. FIGS. 46A and 46B illustrate a detailed flow of thesynchronization establishing processing.

[0681] (a) The BTS starts transmission of a forward channel.

[0682] (b) The mobile station establishes the synchronization of aforward channel on the basis of the synchronization information of theperch channel, and a frame offset group and a slot offset group whichare noticed from the network.

[0683] (c) The mobile station starts transmission of a reverse channelat the same frame timing as the forward channel.

[0684] (d) The BTS establishes the reverse channel synchronization onthe basis of the frame offset group and slot offset group which aredesignated by the MCC.

[0685] In this case, the actual synchronization timings are shifted bythe propagation delay time taken to make a round trip between the mobilestation and the BTS. Thus, the propagation delay time measured at therandom access reception can be utilized to reduce the search range forestablishing the synchronization.

[0686] b.2.2.4. At the Inter-Cell Diversity Handover.

[0687] With regard to the reverse dedicated physical channel transmittedby the mobile station, and the forward dedicated physical channeltransmitted by the BTS which originates the diversity handover, theradio frame number and long code are continuously counted up as usualeven at the beginning of the diversity handover, and are not changedabruptly. The continuity of user information conveyed is fullyguaranteed, and hence no instantaneous interruption takes place.

[0688] The outline of the synchronization establishing procedure at thestart of the diversity handover will be described with reference toFIGS. 88A and 88B.

[0689] (a) The mobile station measures the frame time difference betweenthe same number radio frames that the mobile station is transmittingthrough the reverse dedicated physical channel and the handoverdestination BTS is transmitting through the perch channel, and reportsthe measured results to the network. The measured results are obtainedas the time difference of the frame timing of the reverse dedicatedphysical channel from the frame timing of the perch channel. They arerepresented in terms of chips, and take a positive value ranging fromzero to “reverse long code period −1” chips.

[0690] (b) The mobile station reports, over the ACCH of the reversededicated physical channel, the measured results of the frame timedifference in the form of a layer 3 signal to the BSC through thediversity handover originating BTS.

[0691] (c) The BSC notifies using the layer 3 signal the diversityhandover destination BTS of the measured results of the frame timedifference along with the frame offset and the slot offset which are setat the at the incoming or outgoing call connection.

[0692] (d) The handover destination BTS, receiving the notification ofthe measured results of the frame time difference, frame offset and slotoffset, starts the transmission of the forward dedicated physicalchannel using the received information, and starts the synchronizationestablishing processing of the reverse dedicated physical channel themobile station is transmitting. About the transmission timing of theforward dedicated physical channel, and the synchronization establishingmethod of the reverse dedicated physical channel, refer to 4.1.3.

[0693] 5.2.2.5. Synchronization of Perch Channels of other Sectors inthe Same Cell.

[0694] Each sector in the same cell transmits the perch channel which isspread using the same long code and the same short code, with keepingthe phase difference specified by the system. The mobile stationreceives broadcast information from waiting sectors after completing theinitial synchronization. The broadcast information includes the sectornumber of its own and the number of sectors in the same cell. The mobilestation identifies the long code phases of the other sectors in the samecell, and establishes the perch channel synchronization.

[0695] 5.2.2.6. A Method of Deciding the Synchronization Establishmentof Dedicated Channels.

[0696] (a) Chip synchronization. The BTS knows the reverse long codephase of the channel to be received. The BTS carries out path search,and RAKE reception of the paths with high correlation detection values.If the transmission characteristics described at 5.1.2. are satisfied,the RAKE reception is readily possible.

[0697] (b) Frame alignment. Since the long code phase has one-to-onecorrespondence with the frame timing, the search for the frame timing isnot needed principally. It is enough to check the frame alignment at theframe timing corresponding to the long code phase after the chipsynchronization has been established. The decision condition of theframe alignment establishment of the BTS for the dedicated physicalchannel is that the radio frames whose sync words each include Nb orless unmatched bits continue for SR frames or more.

[0698] (c) Super frame alignment. Since the dedicated physical channeldoes not include any bit indicating the FN, the frame number is tacitlydecided to establish the super frame alignment. As to the reversededicated physical channel, the frame number is set such that the framenumber becomes zero at the timing lagged behind the timing at which thereverse long code phase is zero by an amount of the frame offset+slotoffset as shown in FIGS. 87A and 87B. This relationship between the longcode phase and the frame number is maintained until the radio channel isreleased, even if the diversity handover is repeated after the incomingor outgoing call connection.

[0699] As to the forward dedicated physical channel, the frame number isdetermined such that the radio frame whose timing is shifted by apredetermined time period from the perch channel frame timing isprovided with a frame number equal to the SFN of the perch channel,modulo 64. The predetermined time period equals frame offset+slot offsetduring the incoming or outgoing call connection as illustrated in FIGS.87A and 87B. During the diversity handover, it equals the measured valueof the frame time difference −½ slot −α, where a is an omitted value forexpressing the measured value of the frame time difference −½ slot interms of a symbol unit.

[0700] (2) Resynchronization. The present system does not possess anyspecial resynchronization establishing processing procedure because theoptimum path search by the searcher is equivalent to carrying outcontinuous resynchronization.

[0701] (3) An out-of-phase decision method. An out-of-phase decisionmethod of the BTS in the radio section for the dedicated physicalchannel will now be described. The following two conditions aremonitored.

[0702] Condition 1: Whether or not the number of unmatched bits in async word is equal to or less than Nb.

[0703] Condition 2: Whether or not the CRC on the DTCH selectioncombining unit basis or on the UPCH internal encoding unit basis iscorrect.

[0704] If the radio frames that satisfy neither of the two conditionscontinue for SF frames or more, a decision is made that the out-of-syncstate takes place, where SF is the number of forward synchronizationguarding stages. If the radio frames that satisfy at least one of thetwo conditions continue for SR frames or more in the out-of-sync state,a decision is made that the synchronous state takes place, where SR isthe number of reverse synchronization guarding stages.

[0705] 5.2.4. Handover Control.

[0706] 5.2.4.1. Inter-Sector Diversity Handover in the Same Cell.

[0707] It is assumed that the number of sectors involved in theinter-sector diversity handover in the same cell is three at themaximum.

[0708] (1) Reverse link. The maximal ratio combining is carried out forthe entire symbols of the physical channel in the same manner as thespace diversity of the received signals from a plurality of sectorantennas. The forward transmission power control is carried out usingthe TPC symbols after the maximal ratio combining. The reversetransmission power control is carried out using the receive qualityafter the maximal ratio combining. That is, the forward TPC symbols areset using the receive quality after the maximal ratio combining. As forthe Wlre transmission, the link establishment and transmission arecarried out in the same manner as when the diversity handover is notbeing performed.

[0709] (2) Forward link. With regard to each symbol on the physicalchannel, the same symbol is transmitted from the plurality of the sectorantennas. The transmission timing control is carried out in the samemanner as the inter-cell diversity handover (see 4.1.3 for moredetails). As for the wire transmission; the link establishment andtransmission are carried out in the same manner as when the diversityhandover is not being performed.

[0710] 5.2.4.2. Inter-Cell Diversity Handover.

[0711] The transmitted and received signal processings of both theforward and reverse links during the inter-cell diversity handover arecarried out in the same manner as when the diversity handover is notbeing performed.

[0712] 5.2.5. Packet Transmission Control.

[0713] 5.2.5.1. Applications.

[0714] The packet transmission control is applied to the followingservices.

[0715] TCP/IP packet service.

[0716] Modem (RS-232 serial data transmission) service.

[0717] 5.2.5.2. Outline.

[0718] The purpose is to transmit data of various trafficcharacteristics from low density light traffic to high density heavytraffic with efficiently utilizing radio resources and facilityresources. Major features will be described below.

[0719] (1) Switching of physical channels in use in accordance withtransmission functions such as traffic. To make effective use of theradio resources and facility resources without degradation in thequality of service, the physical channels (logical channels) areswitched as needed in accordance with the transmission functions liketime varying traffic volume. During light traffic: common controlphysical channels (FACH and RACH). During heavy traffic: dedicatedphysical channels (UPCH)

[0720] (2) Switching control of the physical channels between the MS andBTS.

[0721] The switching control between the physical channels are carriedout frequently. If the switching control involves the wire transmissioncontrol, this will lead not only to an increase of a wire transmissioncontrol load, the wire transmission cost and the control load of the BSCand MSC, but also to an increase in the switching control delay,resulting in the degradation in the quality of service. To avoid this,the switching control must be carried out only between the MS and BTS,thereby obviating the wire transmission control and BSC and MSC controlinvolved in the switching control.

[0722] (3) Inter-cell high speed HHO (hard handover).

[0723] At least while using the common control physical channel, thediversity handover is impossible because the transmitting and receivingtimings cannot be set freely as in the dedicated physical channel. Inaddition, if the normal DHO is applied to the dedicated physicalchannels during the switching control of the physical channels, it isnecessary for the switching control between the dedicated physicalchannels to control a plurality of BTS'es, which will increase thecontrol load and degrade the quality of service because of an increasein the control delay.

[0724] For this reason, hard handover (HHO) is employed as a scheme inthe packet transmission under the condition that the HHO is carried outat a high frequency to avoid an increase in the interfering power due tohandover. Since the HHO is carried out at a high frequency, if the HHOprocessing involves the wire transmission control, this will lead notonly to an increase of a wire transmission control load, that of thewire transmission cost and that of the control load of the BSC and MSC,but also to an increase in the HHO control delay, resulting in thedegradation in the quality of service. To avoid this, the wire sectionuses the diversity handover, and only the radio section employs the HHO.In addition, the HHO control is carried out only between the MS and BTS,thereby obviating the wire transmission control and BSC and MSC controlinvolved in the HHO control .

[0725] 5.2.5.3. Inter-Cell Handover Control.

[0726] An inter-cell handover processing procedure will now be describedwith reference to the processing sequence of FIG. 47.

[0727] (1) As in the normal DHO, the mobile station selects sectors thatmeet the diversity handover start conditions in accordance with theperch channel received levels of the peripheral sectors, and reportsthem to the BSC via the BTS.

[0728] (2) The BSC establishes a wire channel link with the diversityhandover destination BTS so that a plurality of links are connected tothe DHT, and the wire section is brought into a DHO state.

[0729] (3) The mobile station continuously measures for each BTS thepropagation loss between the BTS and MS using the perch channel receivedlevel of the present location sector and the perch channel receivedlevels of other sectors involved in the handover, and compares themeasured propagation losses. If the propagation loss of one of the othersectors involved in the handover becomes less than that of the presentlocation sector, and their difference exceeds a predetermined value, thestart of the hard handover is decided. Thus, the mobile station firstsends to the present location sector a request for halting thetransmission and reception of the packet data.

[0730] (4) Sending a response signal back to the mobile station, the BTSin the sector in which the mobile station is located halts thetransmission and reception of the packet data over the radio section,and releases the radio link. The wire link which has been established,however, is unchanged.

[0731] (5) Receiving the response signal from the BTS in the currentlocation sector, the mobile station releases the radio channel betweenthem, and transmits over the RACH a transmitting and receiving requestsignal of the packet data to the BTS in the handover destination sector.This signal is transmitted through the physical channel (common controlphysical channel or dedicated physical channel) which was used by thehandover originating BTS.

[0732] (6) The handover destination BTS establishes a physical channelthat is to be set for the packet data transmission in accordance withthe received RACH signal that includes information about the physicalchannel (common control physical channel or dedicated physical channel)used by the handover originating BTS. Although the wire link set-up isnot changed in any way, the connection between the wire link and radiolink is designated. The sequence of the processing is the sameregardless of the physical channel (common control physical channel ordedicated physical channel) in use. Only, in establishing/releasing theradio link, the physical channel establishing/releasing processing isrequired with the dedicated physical channel but not with the commoncontrol physical channel.

[0733] 5.2.5.4. Inter-Sector Handover Control.

[0734] FIGS. 48-51 shows examples of the connection configuration duringthe inter-sector handover. With regard to the dedicated physical channel(UPCH), since the inter-sector DHO is controllable independently of the.BTS, the inter-sector DHO that uses the maximal ratio combining iscarried out for both the forward and reverse links in the packettransmission as in the circuit switching mode.

[0735] With regard to the common control physical channel (FACH andRACH), since the transmitting and receiving timings cannot be setfreely, the maximal ratio combining is impossible for both the forwardand reverse links. For this reason, the switching control is carried outin the BTS and mobile station such that the transmission and receptionare carried out with only one sector in accordance with the propagationloss of the perch channel. The switching control method is the same asthe inter-cell handover processing as shown in FIG. 47.

[0736] 5.2.5.5. Switching Control of the Physical Channels.

[0737] (1) Switching decision node. The BTS that covers the locationsector of the mobile station makes a decision of the switching on thebasis of the following factors.

[0738] (2) Factors for making a switching decision. The followingfactors are available, and the factors to be used are selectable. Thefactors 1 and 2 become available when the report of the informationabout the factors is started.

[0739] Factor 1: In-band information (information about the physicalchannel which is desired to be used) fed from the ADP of the MCC and theADP of the MS.

[0740] Factor 2: Monitoring of the forward/reverse traffic volume by theBTS.

[0741] Factor 3: A layer 3 signal that requires from the MS to the BTSswitching of the channel to be used.

[0742] (3) A switching decision method. A decision of switching is madeby comparing the information reported by the factors of the foregoingsection (2) with predetermined thresholds.

[0743] (4) A switching control method. FIGS. 52 and 53 illustrateswitching sequences. For example, when the mobile station (MS) and thebase station (BTS) is communicating through a common control physicalchannel (FIG. 52), the BTS makes the switching decision if anyone of theforegoing switching decision factors takes place. When making aswitching as a result of the decision, the BTS instructs through theFACH the MS to establish a dedicated physical channel, and establishesthe designated dedicated physical channel between the MS. Then, the BTSchanges the connection of the wire link and radio link with the MS fromthe common control physical channel to the dedicated physical channel.Subsequently, the BTS communicates over the dedicated physical channelwhich has been established.

[0744] On the other hand, when the mobile station (MS) and the basestation (BTS) is communicating through a dedicated physical channel(FIG. 53), the BTS makes a decision of the switching to a common controlphysical channel. When a switching to the common control physicalchannel is required, the BTS instructs through the UPCH the MS torelease the dedicated physical channel which is being used. Receivingthe instruction to release the dedicated physical channel, the MS makesa response to that, and releases the dedicated physical channel which isbeing used. Then, the MS starts the FACH reception of the commonphysical channel.

[0745] Receiving the response, the BTS releases the dedicated physicalchannel which is used between it and the MS, and changes the connectionof the wire link and radio link with the MS. Subsequently, the BTScommunicates over the common control physical channel which has beenestablished. The switching control is processed only in the radiosection between the mobile station and the BTS, without involving BSCand wire section at all.

[0746] Since the switching control is based only on the decision thebase station makes, and does not involve any switching control of thewire section (between the base station and the control center (BSC), forexample), it is possible to reduce the load of the switching control,and to speed up the switching control.

[0747] The control signal between the mobile station and the BTS is alayer 3 signal, and is processed by the BTS. In this case, the BTS mustchange the connection between the wire link and radio link in accordancewith the instructions as described before.

[0748] 5.3. Transmission Path Interface.

[0749] 5.3.1. Physical Interface Terminating Function.

[0750] Electric level interface.

[0751] Cell level interface.

[0752] a) Generation/termination of transmission frames. Mapping ATMcells using a 6.3M/1.5M transmission path based on the PDH(plesiochronous digital hierarchy).

[0753] The ATM cells are transmitted at 6.3M using TS1-TS96 withoutusing TS97 and TS98, and at 1.5M using all the TS1-TS24. In this case,although it is unnecessary to recognize the delimiter between the 53bytes of the ATM cells, the delimiters between time slots and betweenoctets of the ATM cells are transmitted in conjunction with theboundary.

[0754] On the receiving side, the ATM cells are extracted from theTS1-TS96 with ignoring the data of the TS97 and TS98, at 6.3 M. At 1.5M, the ATM cells are extracted from the TS1-TS24.

[0755] b) Cell synchronization establishment.

[0756] 1) First, to identify the cell boundary, using a fact that thedelimiter of each octet is instructed from the physical channel beforethe cell synchronization, the header error control code on every fouroctet basis is calculated by the generator polynomial X⁸+X²+X+1 withshifting everyone octet, until its result becomes equal to the mod 2value of the fifth octet value minus “01010101”.

[0757] 2) Once a position is detected at which the HEC (Header. ErrorCorrection) value equals the calculation result, a pre-synchronizationstate is started assuming the position as the header position.

[0758] 3) Subsequently, it is assumed that the header position takesplace everyone cell (53 bytes) interval, and the HECs are checked at theintervals. Thus, if six consecutive HECs are found to be correct, thesynchronization state is started.

[0759] 4) The HEC check operation is continued at everyone cell intervalin the synchronization state to monitor the state. Even if HEC errorsare detected, if the consecutive number of the HEC errors is less thanseven, the synchronization state is maintained because of thesynchronization guarding. An out-of-sync state is decided if sevenconsecutive HEC errors take place, and the control is returned to thestate of 1) for resynchronization.

[0760] c) Cell rate adjustment. When the ATM cell rate of the ATM layerdiffers from the transmission path rate as in the case where no cell ispresent to be sent on the transmission path, the physical interfaceinserts idle cells for adjusting the cell rate and for matching the tworates.

[0761] Since the idle cell has a fixed pattern, its header can beidentified by “00000000 00000000 00000000 00000001 01010010”. Itspattern in the information field consists of iterative sequences of“01101010” (see, FIG. 32).

[0762] The idle cell is used only for cell synchronization on thereceiver side, without any other role. Cell level scrambling (appliedonly to 6.3 M).

[0763] 1) Only information field bits are made random by the generatorpolynomial X43+1 at the cell level.

[0764] 2) Descrambling is halted in the hunting state of the cellsynchronization.

[0765] 3) The descrambling operates over the bits equal to theinformation field length in the pre-synchronized state and in thesynchronization established state, and halts during the period assumedto be the next header.

[0766] 4) This function can be enabled or disabled by a hard switch.

[0767] 5.3.2. ATM Terminating Function.

[0768] ATM cell VPI/VCI identification. ATM cells have different VCI/VPIfor each application or for each user, and transfer themselves torespective processing sections by identifying the VPI(VCI.

[0769] ATM cell VPI/VCI multiplexing. Since different vcrs aremultiplexed on each VPI basis to be transmitted in the reverse directionsignal, each application outputs its reverse direction ATM cell signalwith band assurance control.

[0770] Cell header structure. The ATM cell comprises a cell header asshown in FIG. 54. The cell header includes 8-bit VPI and 16-bit VCI, andthe details of their coding are specified separately between theswitching system and the base station.

[0771] ATM header coding. The transmission order of bits of the ATM cellis determined such that the bits in each octet are sent from the bitnumber 8, and the octets are sent from the octet number 1. Thus, theyare transmitted from the MSB. As for the routing bits of the VPI/VCI,there are specified three types of VPIs in the interface between thebase station and the switching center, and 256 types (8 bits) of VCIsfrom 0-255.

[0772] Channel number/VPI/VCI setting (initial state).

[0773] Channel number: The channel number is fixedly corresponds to themounted position of a HW interface card and the connector position inthe card.

[0774] VPI: The VPI is always “0” (not used in practice).

[0775] VCI: The VCI is specified when a link of a wire transmission pathis established.

[0776] 5.3.3. AAL-Type 2 Control Function.

[0777] AAL-Type 2 protocol. The AAL-Type 2 protocol is intended toprovide variable rate services that have timing dependence between thetransmitting and receiving ends, such as voices which are subjected tovariable rate encoding. The detail of the specifications is based onITU-TI. 363.2.

[0778] a) Service types (Required conditions, etc.). AAL-2 is requiredto carry out real time data transfer to the higher layer betweentransmitting and receiving sides at a variable rate, with particulartiming conditions. In addition, it is required to achieve informationtransfer for matching the clock and timing between the transmitting andreceiving sides, and to carry out transfer of information about datastructure.

[0779] b) Functions of AAL-2. The AAL-2 must have the capability ofdealing with, besides the timing conditions like those of AAL-1,multiplexing for multimedia multiplexing of data and voice, and ofhandling a variable rate, cell loss and cell priority.

[0780] 5.3.4. Forward Direction Signal Separation Procedure.

[0781] The control signal and traffic signal in a forward directionsignal can be separated by first identifying the AAL type. There areAAL-2 and AAL-5 in the AAL type, and they can be identified by the VCI(see, 4.2.2.1.).

[0782] Likewise, the control signal between the BTS and MCC in the AAL-5connection can be separated from the super frame phase correction cellby the VCI because their VCIs are different.

[0783] The AAL-2 connection further includes CIDs for identifying users,and carries out the separation using the CIDs that are different foreach call.

[0784] 5.3.5. Band Assurance Control.

[0785]FIG. 55 illustrates the outline of the band assurance control. Theband assurance control determines the transmission order of short cellsand standard cells in accordance with the following quality classes, andestablishes respective bands.

[0786] More specifically, the band assurance control, being based on theprecondition that the short cells and standard cells are discarded ifthey exceed a maximum tolerable delay time, determines transmissionorders of the short cells and standard cells for respective qualityclasses such that the cell loss ratio becomes equal to a maximum cellloss ratio. The setting method of the transmission order is specified.

[0787] As with the VCs to which the AAL-Type 5 is applied, the VCI isassociated with one of the following AAL-Type 5 quality classes bysetting a MATM connection ID.

[0788] As with the VCs to which the AAL-Type 2 is applied, the VCI andCID are associated with one of the following AAL-Type 2 quality classesby setting the MATM connection II).

[0789] 5.3.5.1. Quality Classes.

[0790] 5.3.5.1.1. AAL-Type 5 Quality Classes.

[0791] The following six requirements are needed for the AAL-Type 5quality classes. Table 28 shows the correspondence between services andthe quality classes. In practice, the quality class is set inconjunction with the connection establishment of the wire transmissionpath. The timing cell VC is always assigned top priority (delay time is0 ms, and loss rate is 0).

[0792] (maximum tolerable delay time; ratio); allowable cell loss

[0793] (top priority of 0 ms delay; loss ratio 0)

[0794] (5 ms; 10⁻⁴)

[0795] (5 ms; 10⁻⁷)

[0796] (50 ms; 10⁻⁴)

[0797] (50 ms; 10⁻⁷)

[0798] (AAL-Type 2)

[0799] 5.3.5.1.2. AAL-Type 2 Quality Classes.

[0800] The following four requirements are needed for the AAL-Type 2quality classes. Table 28 shows the correspondence between services andthe quality classes. In practice, the quality class is set inconjunction with the connection establishment of the wire transmissionpath.

[0801] (maximum tolerable delay time; allowable cell loss ratio)

[0802] (5 ms; 10⁻⁴)

[0803] (5 Ms; 10⁻⁷)

[0804] (50 ms; 10⁻⁴)

[0805] (50 ms; 10⁻⁷)

[0806] When there are a plurality of AAL-Type 2 VCs as shown in Table28, the, band assignment to the AAL-Type 2 quality classes can be madedifferent for each VC. In other words, the transmission order of theshort cells can be changed for each VC.

[0807] 5.3.5.2. Band Assurance Function of Reverse Direction Signals.

[0808] As with the reverse direction signals, it is necessary to achieveboth an AAL-Type 2 level band assurance and an ATM cell level bandassurance which includes both the AAL-Type 2 and the AAL-Type 5.

[0809]FIG. 56 illustrates a transmission procedure of the reversedirection ATM cell, and FIG. 57 illustrates an assembling procedure ofreverse direction co-transmitted cells of the AAL-Type 2 level.

[0810] The cell transmission sequence data is specified incorrespondence with the quality classes at the start up of the BTS. Inaccordance with the cell transmission sequence data, short cells andstandard cells to be transmitted are selected from the quality classes,subjected to the multiplexing, and formed into transmission cells.

[0811] If a cell of the target quality is not present in the buffer, acell in the next quality can be transmitted. According to the tolerabledelay times determined for the individual quality classes, a cell in thebuffer that exceeds the tolerable delay time of its class is discarded.

[0812] FIGS. 58A-58C show examples of the cell transmission sequencedata corresponding to Table 28. Transmission cycles of A, B. C, . . . ,L are determined in accordance with allocated bands of respective ATMbands A, B, C, . . . , F (for example, ACADAFAC . . . ). In addition,transmission sequences for compositing the short cells are determineddepending upon respective SC bands E1-F4 such that the respectivequality classes are satisfied (for example, F2F1F2F3F4 . . . ).

[0813] If a cell is not present in the target class, a cell in the nextpriority is transmitted. A cell in the interrupt class is alwaystransmitted with the top priority. TABLE 28 Correspondence betweenservices and quality classes. ATM quality SC quality classes classes(tolerable (tolerable delay, cell loss delay, cell loss ATM SC ratio)ratio) Services band band (Top Priority) — Timing cell — — (5 ms; 10⁻⁷)Packet A — (5 ms; 10⁻⁴) — Packet B — (50 ms; 10⁻⁷) — Control signal C —between BTS, MMC and SIM, paging signal (50 ms; 10⁻⁴) — Packet D — (5ms; 10⁻⁷) unrestricted 32 kbps E E1 unrestricted 64 kbps AAL-Type 2 (5ms; 10⁻⁴) voice E2 VC1 (50 ms; 10⁻⁷) ACCH (all symbol rates) Packet E3(50 ms; 10⁻⁴) Modem E4 Fax (5 ms; 10⁻⁷) unrestricted 32 kbps F F1unrestricted 64 kbps AAL-Type2 (5 ms; 10⁻⁴) voice F2 VC2 (50 ms; 10⁻⁷)ACCH (all symbol rates) Packet F3 (50 ms; 10⁻⁴) Modem F4 Fax

[0814] 5.3.6. AAL-Type 5+SSCOP Function.

[0815] Service types. The AAL-5 is a simplified AAL type that isprovided for transferring signaling information. It differs from theother AAL types in that its payload has no header trailer, and hence cantransfer 48 bytes with a minimum communication overhead.

[0816] Functions of the AAL-5. The AAL-5 carries out the error detectionnot on a cell by cell basis but on a user frame by user frame basis toimprove the efficiency of the data transmission. The error detection isperformed using CRC-32 check bits. The CRC is given for each user frame,and is effective in a poor transmission quality environment because ofits high detection capability due to 32 bits.

[0817]FIG. 59 shows the format of the AAL-5. The receiving side carriesout the following operations.

[0818] 1) It identifies the delimiters of data considering the value ofthe PT {payload type} of the ATM header.

[0819] 2) It checks the extracted payload by calculating the CRC.

[0820] 3) It identifies the user data by verifying the LENGTHinformation.

[0821] SSCOP protocol sequence (link establishment and release).

[0822] In the SSCOP, the acknowledge or flow control information is nottransferred on the data frame between the base station and switchingcenter, and the role of the data frame is completely separated from thatof the control frame. FIG. 60 illustrates an example of the sequencefrom the establishment to the release of the SSCOP link.

[0823] 5.3.7. Reverse Direction Delay Adding Function.

[0824] The SSCOP is applied to the control signal VC and paging VCbetween the BTS and MCC, and is processed by the BTS and MCC. Thereverse direction delay adding function is provided for measuring systemimmunity by adding delays to reverse signals when carrying out a test ofcombining reverse signals between different base stations. A delay up toa maximum of 100 ms can be added to the reverse signal at every 0.625 msstep (frame offset step). The delay amount can be set by a dip switch.

[0825] 5.3.8. Reference Timing Generating Function (Radio FrameAlignment Function).

[0826] 5.3.8.1. SFN Synchronization.

[0827] The BTS carries out with the MCC the time synchronizationestablishing processing of the SFN (System Frame Number) which will bedescribed below. The SFN clock the MCC generates is the master clock ofthe entire system. The SFN synchronization processing is provided forestablishing in the BTS the time synchronization with the SFN clock ofthe MCC. The target for the range of the time synchronization error isset within 5 msec. The BTS uses as its internal reference clock the SFNclock after the synchronization is established. The timings of thetransmitting and receiving radio channels in respective sectors underthe control of the BTS are generated from the reference SFN clock of theBTS (see, FIGS. 85-88B).

[0828] The SFN synchronization establishment is implemented byexchanging the timing cells between the MCC and BTS. FIG. 61 illustratesthe detail of the procedure which will be described below. The numeralsin FIG. 61 correspond to the numbers in the following descriptions.

[0829] (1) The BTS, at turn-on or at start up after a reset, generates atemporary SFN clock signal.

[0830] (2) The BTS acquires a transmitting time (a time within a superframe, and the super frame position in a long code period) of a timingcell 1 to be transmitted from the BTS to the MCC. The transmitting timeis based on the temporary SFN clock signal.

[0831] (3) The BTS generates the timing cell 1. Values of informationelements in the timing cell 1 are set as shown in Table 29. TABLE 29Information elements Specified values Message ID 03h: Timing Report(BTS→MCC) SF time information (received, MCC-SIM All 0 side) SF timeinformation (transmitted, MCC- All 0 SIM side) SF time information(transmitted, BTS The time within the super side) frame in the timeinformation acquired in (2). LC counter information (received, MCC- All0 SIM side) LC counter information (transmitted, All 0 MCC-SIM side) LCcounter information (transmitted, BTS The super frame position side) inthe long code period in the time information acquired in (2). Otherinformation elements In accordance with Table 26.

[0832] (4) The BTS transmits the timing cell 1 it generates in (3) atthe transmission timing it acquired in (2).

[0833] (5) The MCC receives the timing cell 1, and acquires the receivedtime (the time within the super frame and the super frame position inthe long code period). This time is based on the SFN clock generated bythe MCC.

[0834] (6) The MCC acquires a transmitting time (a time within a superframe, and the super frame position in a long code period) of a timingcell 2 to be transmitted from the MCC to the BTS. This time is atransmitting time based on the temporary SFN clock generated by the MCC.

[0835] (7) The MCC generates the timing cell 2. Values of informationelements in the timing cell 2 are set in accordance with Table 30. TABLE30 Information elements Specified values Message ID 02h: Timing Report(MCC→BTS) SF time information (re- The time within the super frame inthe ceived, MCC side) time information acquired in (5). SF timeinformation (trans- The time within the super frame in the mitted, MCCside) time information acquired in (6). SF time information (trans- Thetime within the super frame in the mitted, BTS side) time informationacquired in (2) (The MCC sets this information element in the timingcell received in (5) to the same value again). LC counter informationThe super frame position in the long code (received, MCC period in thetime information acquired in side) (5). LC counter information The superframe position in the long code (transmitted, MCC period in the timeinformation acquired in side) (6). LC counter information The superframe position in the long code (transmitted, BTS period in the timeinformation acquired in side) (2). (The MCC sets this informationelement in the timing cell received in (5) to the same value again).Other information elements In accordance with Table 26.

[0836] (8) The MCC transmits the timing cell 2 it generated in (7) atthe transmission timing it acquired in (6).

[0837] (9) The BTS receives the timing cell 2, and acquires the receivedtime (the time within the super frame and the super frame position inthe long code period). This time is a received time based on thetemporary SFN clock in the BTS.

[0838] (10) The BTS calculates the corrected value X of the temporarySFN clock phase from the information elements of the timing cell 2 itreceives. FIG. 62 illustrates the calculation method and calculationbasis of the corrected value. Calculation results of the corrected valueare stored in a memory.

[0839] In FIG. 62,

[0840] SF_BTS-1: SF time information about BTS transmission of thetiming cell 1.

[0841] LC_BTS-1: LC counter time information about BTS transmission ofthe timing cell 1.

[0842] SF_MCC-1: SF time information about MCC-SIM reception of thetiming cell 1.

[0843] LC_MCC-1: LC counter time information about MCC-SIM reception ofthe timing cell 1.

[0844] SF_BTS-2: SF time information about BTS reception of the timingcell 2.

[0845] LC_BTS-2: LC counter time information about BTS reception of thetiming cell 2.

[0846] SF_MCC-2: SF time information about MCC-SIM transmission of thetiming cell 2.

[0847] LC_MCC-2: LC counter time information about MCC-SIN transmissionof the timing cell 2.

[0848] (11) The BTS counts the number of corrections, calculatescorrected values, and increments the counter each time it stores thecorrected value.

[0849] (12) The BTS stores as one of the system parameters an upperlimit N of the number of corrections. The BTS iterates the foregoing(2)-(11) until the counter value exceeds the upper limit N which isequal to or less than 255.

[0850] (13) When the number of corrections reaches the upper limit N, astatistical processing is carried out of calculated results of thecorrected values stored. (The statistical processing temporarily selectsthe maximum value from among the calculated results).

[0851] The BTS shifts its temporary SFN clock by the corrected valuecalculated by the statistical processing, thus carrying out thecorrection processing of the SFN clock the BTS.

[0852] (14) Completing the foregoing operations, the BTS lights up anACT lamp the HWY interface card of the BTS assuming that the SFN timesynchronization has been completed between the BTS and MCC. If thesynchronization is not yet established even after a predetermined timehas elapsed from the beginning of the transmission of the timing cell,the BTS stops the transmission of the timing cell, and lights up an ERRlamp on the card including the transmission path interface. In addition,the BTS brings the SFN timing into a free-running state, and performsthe transmission control of the radio section in accordance with thefree-running SFN.

[0853] 5.3.8.2. Synchronization Holding Function.

[0854] The BTS generates the reference clock from the HWY, and generatesvarious clock signals from the reference clock. When the BTS isconnected with a plurality of 1.5 M HWYs, it can select with a hardswitch like a dip switch the HWY used for generating the clock. The BTSgenerates, after establishing the SFN time synchronization at the startup, the reference SFN clock only from the clock that is generated fromthe HWY. If a restart processing is not carried out, the reference SFNclock of the BTS will not be changed by any other factors. The BTS doesnot perform autonomous SFN synchronization correction. Besides, it doesnot carry out a synchronization correction processing triggered by asynchronization correction request from the MCC.

[0855] 5.4. Transfer Processing Method of the Transmission InformationBetween the MCC and MS.

[0856] A transfer processing method by the BTS of the informationtransmitted between the MCC and MS varies depending on the type of thelogical channels in the radio section. The processing method will bedescribed below. The following description has nothing to do with thetransmission information between the MCC and BTS.

[0857] 5.4.1. Correspondence Between Radio Link and Wire Link.

[0858] As for the correspondence between radio section links (physicalchannels and logical channels) and wire section links (channel number,VP1, VC1 and CID), such correspondence is provided as needed.

[0859] 5.4.2. Processing Method of Transmission Information.

[0860] 5.4.2.1. Forward Direction.

[0861] Table 31 shows, for each logical channel, a processing method ofthe transmission information which is received from the wire section.TABLE 31 Processing method of transmission information received fromwire section. Logical channel Description DTCH Assembles a radio unitfrom the transmission information in a received short cell, andtransmits it in a radio frame with the same frame number as the FN inthe SAL of the short cell. Discards the user information in the receivedshort cell if the transmission to the wire section is not completedbefore the expiration of a timer ADTCH which is started when the shortcell is received. The value of the timer ADTCH is specified as one ofthe system parameters in the range from 0.625 msec to 640 msec at every0.625 msec step. Makes OFF the transmission of the DTCH symbols ortransmits dummy data as for a radio frame that does not receive anytransmission information from the wire section. ACCH Assembles, when oneradio unit is placed in one radio frame (in the case of a 256 kspsdedicated physical channel), a radio unit from the transmissioninformation in a received short cell, and transmits it in a radio framewith the same frame number as the FN in the SAL of the short cell.Assembles, when one radio unit is placed in a plurality of radio frames(in the case of 128 ksps or less dedicated physical channel), a radiounit from the transmission information in a received short cell, andtransmits it beginning from a radio frame with the same frame number asthe FN in the SAL of the short cell, followed by the remainder of theplurality of the successive radio frames. Discards the user informationin the received short cell if the transmission to the wire section isnot completed before the expiration of a timer AACCH which is startedwhen the short cell is received. The value of the timer AACCH isspecified as one of the system parameters in the range from 0.625 msecto 640 msec at every 0.625 msec step. Makes OFF the transmission of theACCH symbols as for a radio frame that does not receive any transmissioninformation from the wire section. SDCCH Assembles the CPD PDU for thetransmission information in a received short cell, carries out dividingprocessing at every internal encoding unit, performs processings up toassembling of a radio unit, and transmits it in a radio frame that canbe transmitted first. The controller of the MCC transmits the controlinformation on a CPS- SDU unit basis with spacing such that the rate ofthe SDCCH in the radio section is not exceeded. Thus, it is enough for areceiving buffer of the information from the SDCCH wire transmissionpath to have an area that can accommodate only a few framescorresponding to the CPS- SDU with a maximum length. ACH (for Assemblesthe CPD PDU for the information in a received short cell or packet in astandard cell, carries out dividing processing at every internaltransmission) encoding unit, performs processings up to assembling of aradio unit, UPCH and transmits it in a radio frame that can betransmitted first. If divided into a plurality of internal encodingunits, a plurality of radio units are transmitted successively. TheEx-interface for packets of the MCC transmits the control information ona CPS-SDU unit basis with spacing such that the rate of the UPCH in theradio section, which rate is required at the call setup as a peak rate,is not exceeded. Thus, it is enough for a receiving buffer of theinformation from the UPCH wire transmission path to have an area thatcan accommodate only a few frames corresponding to the CPS- SDU with amaximum length. In a state in which the FACH is established, because therate of the radio section can be lower than the peak rate, a FACH buffermust have a rather large size. Makes OFF the transmission of the UPCHsymbols as for a radio frame that does not receive any transmissioninformation from the wire section.

[0862] 5.4.2.2. Reverse Direction.

[0863] Table 32 shows, for each logical channel, a processing method ofthe transmission information which is received from the radio section.TABLE 32 Processing method of transmission information received fromradio section. Logical channel Description DTCH (32 ksps Assembles ashort cell upon receiving a radio frame, and transmits it dedicated tothe wire section at a timing as early as possible. physical Thefollowing two modes are prepared for the transmission to the wirechannel) section. The mode is designated each time a radio link isestablished. Mode 1: As with the radio frame to which the informationpresence or absence decision of 4.1.9.2. gives a result that notransmission information is present, transmission to the wire section isnot carried out. Even if the CRC check for each selection combining unitproduces an incorrect result, if the information presence or absencedecision of 4.1.9.2. gives a result that transmission information ispresent, the transmission information is sent to the wire section afterthe Viterbi decoding. Mode 2: Transmission information is always sent tothe wire section after the Viterbi decoding. DTCH (64 ksps Assembles ashort cell upon receiving a radio frame, and transmits it or more to thewire section at a timing as early as possible. dedicated Transmissioninformation is always sent to the wire section after the physicalViterbi decoding. channel) ACCH Assembles a radio frame from ACCH bitsin one or more radio frames, and carries out the Viterbi decoding andCRC checking. Assembles a short cell immediately only when the CRCchecking produces a correct result, and transmits the short cell to thewire section at a timing as early as possible. Discards the receivedinformation if the CRC checking produces an incorrect result, and doesnot carry out any transmission to the wire section. SDCCH Carries outthe Viterbi decoding and CRC checking for the transmission informationin a radio frame. Generates the CPS PDU in accordance with the W bitsonly when the CRC checking is correct. Assembles a short cell when thegeneration of the CPS PDU is completed and the CRC checking of the CPSis correct, and sends it to the wire section at the earliest timingavailable. Discards the received information if the CRC checking foreach internal encoding unit produces an incorrect result, so that it isnot involved in generating the CPS. In this case, the CPS PDU isdiscarded in its entirety, and the transmission to the wire section isnot carried out. RACH (for Carries out the Viterbi decoding and CRCchecking for the packet transmission information in a radio frame.Generates, for only the transmission) transmission information with TNbit = 0, the CPS PDU in accordance UPCH with the W bits and S bits onlywhen the CRC checking is correct. Assembles a short cell when thegeneration of the CPS PDU is completed and the CRC checking of the CPSis correct, and sends it to the wire section at the earliest timingavailable. Discards the received information if the CRC checking foreach internal encoding unit produces an incorrect result, so that it isnot involved in generating the CPS. In this case, the CPS PDU isdiscarded in its entirety, and the transmission to the wire section isnot carried out.

[0864] 5.4.3. SAL Setting Method.

[0865] A method for generating the SAL in a short cell or standard cellwill now be described with reference to FIG. 36, when reverse directiontransmission information is sent from the radio section to the wiresection. Refer to Table 22 for a fundamental setting method.

[0866] 5.4.3.1. SAT.

[0867] SAT is always set at “00” for all logical channels.

[0868] 5.4.3.2. FN.

[0869] (1) DTCH.

[0870] The FN of a received radio frame is used as the FN of the SAL ofthe short cell or standard cell including the transmission informationwhich is transmitted by the radio frame.

[0871] As illustrated in FIGS. 87A and 87B, the first chip of the radioframe of FN=0 is shifted from the position at which the reverse longcode phase=0 by the sum of the frame offset value and the slot offsetvalue, and the relation is not changed by the iteration of the DHO.Thus, the FN of the received radio frame is determined on the basis ofthe reverse long code phase by the following expression.

FN=((P _(TOP) −P _(OFS))/C) mod 64

[0872] where P_(TOP) is the phase of the first chip of the receivedradio frame,

[0873] P_(OFS) is the sum of the frame offset value and the slot offsetvalue, and C is the number of chips per radio frame, where C=10240,40960, 81920 and 163840 (chip rate=1.024, 4.096, 8.192 and 16.384 Mcps).

[0874] (2) ACCH.

[0875] When a single radio unit overlays a plurality of radio frames (inthe case of 128 ksps or less dedicated physical channels), the FN of thefirst one of the plurality of radio frames is used as the FN in the SAL.

[0876] A method for deciding the FN of the radio frame is the same asthat of the foregoing (1).

[0877] (3) SDCCH, RACH and UPCH.

[0878] *The FN of the first radio frame of one or more radio framesconstituting the CPS-PDU is adopted as the FN in the SAL. A method fordeciding the FN of the radio frame is the same as that of the foregoing(1).

[0879] 5.4.3.3. Sync.

[0880] (1) DTCH, UPCH and SDCCH.

[0881] The sync is set to “0” if the received radio frame is in thesynchronization state, and to “1” if it is in the out-of-sync state. Fordetails of the processing in the outof-sync state, refer to 5.4.4.below. As for the out-of-sync decision method, refer to 5.2.3. When oneCPS-PDU consists of a plurality of radio frames in the UPCH or SDCCH,the sync is set to “11” only if all the radio frames are out-of-sync.

[0882] (2) ACCH and RACH

[0883] The sync is set to “0”.

[0884] 5.4.3.4. BER.

[0885] (1) DTCH.

[0886] The value of the BER is set on the basis of a result of the BERestimated value degradation decision which is carried out for each radioframe.

[0887] (2) ACCH.

[0888] The value of the BER is set on the basis of a result of the BERestimated value degradation decision which is carried out for each radioframe.

[0889] (3) SDCCH, UPCH and RACH.

[0890] The value of the BER is set on the basis of a result of the BERestimated value degradation decision which is carried out for eachCPS-PDU.

[0891] 5.4.3.5. Level.

[0892] (1) DTCH.

[0893] The value of the Level is set on the basis of a result of thelevel degradation decision which is made for each radio frame.

[0894] (2) ACCH.

[0895] The value of the Level is set on the basis of a result of thelevel degradation decision which is made for each radio frame.

[0896] (3) SDCCH, UPCH and RACH.

[0897] The value of the Level is set on the basis of a result of thelevel degradation decision which is made for each CPS-PDU.

[0898] 5.4.3.6. CRC

[0899] (1) DTCH.

[0900] The value of the CRC is set on the basis of a result of the CRCchecking which is carried out for each selection combining unit.

[0901] (2) ACCH.

[0902] The value of the CRC is set on the basis of a result of the CRCchecking which is carried out for each radio unit.

[0903] (3) SDCCH, UPCH and RACH.

[0904] The value of the CRC is set on the basis of a result of the CRCchecking which is carried out for each CPS-PDU. However, since thetransmission to the wire link is carried out only when the CRC iscorrect, it is substantially “0”, normally.

[0905] 5.4.3.7. SIR

[0906] (1) DTCH

[0907] The value of the SIR is set on the basis of a result of the SIRmeasurement which is carried out for each radio unit.

[0908] (2) ACCH.

[0909] The value of the SIR is set on the basis of a result of the SIRmeasurement which is carried out for each radio unit.

[0910] (3) SDCCH, UPCH and RACH.

[0911] The value of the SIR is set on the basis of a result of the SIRmeasurement which is carried out for each CPS-PDU (if the CPS-PDU rangesover a plurality of radio frames, the: average Value over the pluralityof radio frames is used as the result).

[0912] 5.4.3.8. RCH and RSCN.

[0913] The values of the RCN and RSCN are set in accordance with Table24.

[0914] 5.4.4. A processing Method During the Out-of-Sync Decision.

[0915] Table 33 shows a processing for each logical channel, when theout-of-sync method as described in 5.5.2.3. makes an out-at-syncdecision, in which RACH is not handled because the out-at-sync decisionis not applied to the common control physical channel. TABLE 33 LogicalDescription DTCH Generates a cell whose Sync bit in the SDCCH SAL is setat “1”, and sends the short cell to the wire section every 10 msecinterval until the synchronization is recovered. UPCH A short cell ofthe UPCH does not include user information. The remaining bits of theSAL are as follows: SAT: 00 FN: As an estimated value, one of the values0-63 is set which is incremented at every 10 msec interval. It is setsuch that it keeps continuity from before the out-of- sync decision.BER: 1 Level: 1 CRC: 1 SIR: all 0′s RCN, RSCN: according to Table 27 (asin the synchronization holding state). ACCH Halts transmission to thewire section.

[0916] 5.4.5. Cell Loss Detection.

[0917] The position at which the cell loss takes place is located fromthe following parameters, if the forward data from the MCC does notreach the BTS because of the cell loss in the ATM section. FIG. 63illustrates a flow of the cell loss detection.

[0918] *Frame number (FN): It is used for the cell loss detection in allthe unrestricted services.

[0919] *Radio subchannel number (RSCN): It is used in the unrestrictedservices (128 kbps or more unrestricted services) including within 10 mstwo or more internal encoding CRC providing units.

[0920] *Radio channel number (RCN): It is used in the unrestrictedservices implemented by multicodes.

[0921] *UUI (CPS-User to User Indication): It is used when the internalencoding CRC providing unit exceeds the user payload length of the shortcell, which is 42 octets when either the RCN or RSCN is used, and 43octets when none of the RCN and RSCN is used.

[0922] The cell loss is detected using the foregoing four parameters.

[0923] Table 34 shows the processing method of the cell loss detection.TABLE 34 Processing method of cell loss detection. Logical channelProcessing method DTCH Inserts dummy data (all 0's) for each short cellin the cell loss portion, assembles one or more radio frames andtransmits them. ACCH Not necessary to consider the cell less. SDCCHDiscard the entire CPS-SDU including FACH (for packet transmission) asits part the cell loss portion. UPCH

[0924] As described above, the novel base station equipment of themobile communications system in accordance with the present invention isbest suited for high speed CDMA digital communications.

[0925] The present invention may be embodied in other specific formswithout departing from its spirit or essential characteristics. Thedescribed embodiments are to be considered in all respects only asillustrative and not restrictive. The scope of the invention is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes which come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed is:
 1. A base station comprising; means forcommunicating with a mobile station by using a channel: and means forcarrying out, during a communication with the mobile station. switchingcontrol of channels used for the communication.
 2. The base station asclaimed in claim 1, wherein the means for carrying out the switchingcontrol carries out the switching control in accordance with trafficvolume between the base station and the mobile station.
 3. The basestation as claimed in claim 1, wherein the means for carrying out theswitching control carries out the switching control between a channelused in common for communications between the base station and aplurality of mobile stations, and a channel used only for acommunication between the base station and a single mobile station.